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Whether you're buying a new PC, or upgrading an old one, perhaps with a new motherboard, then your choice of processor will be critical. But there's a lot to consider.

Will you opt for AMD, or Intel, for instance? How much performance do you really need? How many CPU cores will it take to achieve that? What might you be able to achieve for overclocking? And how much is all this going to cost? The list goes on, and on.

Fortunately, while there's a huge list of processors available, it's actually not that difficult to reduce the selection to more practical and manageable levels. You just have to take the process step by step, analysing your needs and looking at the best candidates to fulfil them, and this begins by thinking about the age-old question: Intel or AMD?

Intel vs AMD

You might well already have chosen your preferred CPU manufacturer, of course. Maybe you always go with one particular company. Or perhaps you have your motherboard already, in which case the decision has been made already: you'll have to opt for whatever is compatible.

If not, though, selecting Intel or AMD will pose an interesting dilemma.

Right now, Intel is the performance king. Its Core i7 range is blisteringly fast and, initially at least, outperform anything that AMD has to offer.

This comes at a price, though - if you're looking for value, then AMD offers a much better deal. As we write, for instance, the quad-core AMD Black Edition Phenom II X4 965, one of AMD's fastest processors, can be yours for around £130. Intel's core i5-680 delivers roughly equivalent performance, but will cost you maybe £230. And becoming a speed king via something like Intel's Core i7-950 will virtually double the figure again: you can expect to pay £450 or more.

(These figures change day to day, but AMD will remain the value choice for the foreseeable future. If you already have a few CPUs in mind, check our processor section for reviews and more up-to-date price comparisons.)

It's also worth factoring in the price of the motherboard. Spending just £60 to £70 will give you plenty of possible homes for a high-end AMD CPU; opt for the best that Intel has to offer and you'll probably spend at least twice as much. (But again, visit our motherboard pages for up-to-date prices.)

If you want and need Intel's performance then things aren't quite as bad as they seem. Intel CPUs are generally a little more overclockable than AMDs, and something like the i5-750 (priced around £150 as we write) can be pushed a very long way.

But if you don't require that kind of high-end power (or you just can't afford it) then an AMD processor is the way to go. You'll still get plenty of speed when you need it, and will save a pile of cash, too.

Intel Core i7-930 review

Processor features

These days the CPU features that attract the most attention are the number of cores, and its clock speed. Both are simple concepts to understand, but you still have to be careful how you interpret them.

AMD's Black Edition Phenom II X6 1090T, for example, contains six cores, individual processors, which means the CPU can work on six separate tasks at the same time. And each of these runs at a very respectable 3.2GHz.

Meanwhile the Intel Core i7-860 has only four cores, and runs at a mere 2.8GHz. So you might, not unreasonably, expect it to be slower. However, it supports Intel's Hyper-Threading technology, providing an extra four "virtual" cores, and thanks to this, and a few other design decisions, it actually outperforms the Phenom II X6 1090T. So you can't rely solely on these figures to determine which CPU is best.

Still, as a general rule for processors from the same manufacturer, the more cores a CPU provides, the happier you're going to be. You won't see large speed increases from all programs - the popular LAME encoder is still single-threaded, for instance, so upgrading from a dual to quad-core CPU won't deliver any noticeable changes - but most apps that could benefit significantly from multithreading, now do so, and will take advantage of the extra processing power. And just about everything else will be upgraded over time.

Cores should be your first priority, then: you'll want a quad-core CPU at a minimum. After that, opt for the highest clock speed you can afford, or need, but don't worry about that quite as much. You can often ramp that up later with a little judicious overclocking.

GOOD BUY: Quad-core i7 CPUs are excellent performers, easily outpacing the AMD competition

Intel Core i5-750 review

Socket set

Every processor comes sized to fit a particular "CPU socket", a component that connects the CPU to a motherboard. If you've chosen your motherboard already then you'll know what this is; if not, then now might be a good time to think about it, as your processor will need to be compatible.

If you're opting for an AMD CPU then there a couple of options. The cheapest is to go for a Socket AM2+ motherboard, but choosing Socket AM3 instead will get you support for faster DDR3 RAM. AM3 boards will typically also come with USB 3.0 and SATA 6 Gbps, and prices are so affordable that it makes little sense to go for anything else.

If you're choosing an Intel Core i5 CPU then there's even less to think about: you'll want an LGA1156 motherboard.

But if you're splashing out on a Core i7 then it's a little more complicated.

You could buy a Core i7 CPU that also fits the LGA1156 motherboard. These are known as the 800 series, so they'll all have product numbers that are 800 and something: the Core i7-860, say. This will save you a little money, but the LGA1156 boards have some limitations, and for example are often lacking in PCI Express lanes, cutting your expansion possibilities.

The alternative is to buy a Core i7 CPU designed for LGA1366 motherboards, which means 900 series chips like the Core i7-930 or -940. Not only is the board more powerful, but it's also reasonably future-proof. High-end Intel releases like the 6-core i7-975 are already available in the LGA1366 format only, for instance.

If you're building a power system, need plenty of PCI Express power (perhaps to install multiple graphics cards) or want to ensure your system's future upgradeability, then, an LGA1366 board is the way to go.

But if a Core i7 CPU already feels more expensive than you'd really like to pay, and you're just building a regular system, then an LGA1156 board and processor will be fine. Avoid the PCI Express issues and there's little difference in performance, and you can put the money you save towards enhancing another area of your PC.

CHOOSE WISELY: Your choice of motherboard will define exactly which CPUs you can install

Intel Core i7-980X review

CPU options

We've reduced the original mountain of possible CPUs to just a handful, then, but to choose the right model from these you'll need to understand just a few more processor-related terms.

As we've mentioned, many Intel CPUs include a feature called Hyper-Threading, which allows each core to run two sets of instructions simultaneously. It can be a very effective technology - Intel Core i7 CPUs are essentially i5's with Hyper-Threading enabled - and you'll want to get it if you can.

Every Intel processor also contains an amount of embedded memory called a cache, which is used to hold regularly-used information. If the CPU needs this again then it can be fetched from the cache, which is far quicker than accessing system RAM. Look for descriptions like L2 (Level 2 Cache), L3 (Level 3 Cache) or "Intel Smart Cache" (which means L3) - the more your processor has, the better.

And it's a similar story with AMD CPUs, although less dramatic. Opt for a quad-core Phenom II X4 and you'll find they all have the same cache amounts, 2MB for L2, 6MB for L3. The 6-core Phenom II X6 increases L2 cache to 3MB, though, while will provide a useful speed increase in many situations.

What you might want also to consider, though, is the Phenom II's "Thermal Design Power" (TDP), the maximum amount of power it's likely to consume when busy running applications. This ranges from 65W (Phenom II X4 905e or 910e) to 125W (Phenom II X4 955 and higher); the low TDP CPUs are slower, but use less electricity and run cooler, making them better choices for media centre PCs where you want to keep fan noise to a minimum.

You should now have a better idea of what you want from a CPU, then - but you'll still need to find confirmation of exactly which model is best for you. And our processor reviews are a great place to start. There are over 100 reviews online, all filterable by socket, CPU type and more, and with instant price comparisons to hand you'll soon locate the best CPU deals around.

NOT THE BEST: It's a great CPU, but the Intel Core i5 750 lacks Hyper-Threading, reducing its performance a little

Intel Core i7 875K review

AMD believes that processor cores should be built to purpose, unveiling its plans for "Bulldozer" architecture offering performance and "Bobcat" cores that are built for smaller devices.

AMD is keen to compete with Intel in the processor world, and believes that the best way to do this is with two defined core strategies.

Bulldozer

Chips with Bulldozer architecture, which will be manufactured with the latest 32nm SOI technology, will offer 'performance and scalability' and will be aimed at mainstream client and server markets.

The high performance processor core technology will be appearing in the company's chips in 2011 and is a completely new design.

It features what AMD describes as an 'innovative design that delivers true core functionality by pairing two integer execution cores with components that can be shared as needed."

There are instruction set extensions to increase capability and extensive new power efficiency innovations.

This, AMD believes, offers 33% more cores and an estimated 50 per cent increase in throughput 'in the same power envelope as Magny-Cours'.

Bobcat

Next up is "Bobcat" – a small efficient low power x86 core that is likely to be utilised in portable devices.

It is a sub-one-watt capable core which features an out-of-order execution engine, is easy to re-use and offers complete ISA support.

It will make its appearance in AMD's first APU "Ontario" next year, and the estimate is that it will offer "90 per cent of AMD's current mainstream notebook CPU in less than half the area and a fraction of the power".

Interesting stuff, and we will see if AMD reaps the benefit in 2011.

Intel's annual IDF techfest in San Francisco kicks off in a few weeks and that means rumours regarding Sandy Bridge specs are reaching a crescendo.

Sandy Bridge is Intel's next-generation PC processor architecture.

That's right, Intel is tooling up for yet another major update of its CPU tech. Frankly, Intel's current Nehalem-class processors are more than powerful enough for most people's needs. More to the point, they're still much faster than anything Intel's main rival AMD can manage.

But Intel's relentless "Tick Tock" strategy demands either a new architecture or a new production node each year. The end of 2009 saw the first 32nm chips rolling out of the fabs. Thus, the dying days of 2010 will see Sandy Bridge kick in.

Sandy Bridge roadmap

Intel hasn't released full details of the Sandy Bridge product family. But putting the hard info Intel has given us together with some of the more solid rumours, it looks certain the first Sandy Bridge chips out of the gate will be dual and quad-core models.

We also know that Sandy Bridge processors will retain Intel's existing Core i3, i5 and i7 branding but will dump the existing three-digit model suffix in favour of a new four-digit "2000" series indicator.

Thus the entry level chip will be the dual-core 3.1 GHz Core i3-2100, with the quad-core 3.1GHz-Core i5 2400 slotting into the midrange and the 3.4GHz Core i7-2600 quad topping things out at launch. Further dual and quad-core chips will fill in the gaps

Sandy Bridge performance

Six and eight-core chips will also follow later in 2011. But all this talk of core counts and clockspeeds doesn't necessarily tell us much about Sandy Bridge performance. It is an all-new architecture, after all, and that could mean a big boost in core-for-core and clock-for-clock performance.

Problem is, Intel snagged all the low hanging fruit in terms of easy performance gains with the Nehalem architecture. You can only bring features like the memory controller on-die once, for instance. Moreover, we know that Sandy Bridge is not a radical new architecture in the mould of AMD's upcoming Bulldozer [link: ]. Instead, it's a major overhaul of Nehalem.

Sandy Bridge benchmarks

With that in mind, you might not expect any fireworks when the first official benchmark results are published. However, when it comes to floating point performance Sandy Bridge has a trick up its sleeve. Intel has cooked up a new set of instructions known as Advanced Vector Extensions or AVX. Think of AVX as a supercharged version of SSE with data width doubled to 256-bit and you'll get an idea of the potential processing power.

As for all-round CPU performance, reliable numbers are currently hard to come by. However, early engineering samples have begun to leak into the wild. If the handful of benchmarks posted on web forums can be believed, a 2.5GHz quad-core Sandy Bridge processor delivers performance equivalent to a quad-core Nehalem-class chip running north of 3GHz. If true, Intel will have worked some serious magic.

Sandy Bridge graphics

The final major piece of the Sandy Bridge puzzle is graphics. Both dual and quad-core flavours of Sandy Bridge will be available with a graphics core integrated into the CPU die itself. Early die shots indicate the core is compact, only occupying a small proportion of the overall die. That's in contrast to AMD's first CPU-GPU "fusion" processor, which purportedly packs a massive graphics core.

What's more, Intel has been up front about the fact that the new core is derived from Intel's existing integrated graphics technology. We'll have to wait for the next major architectural shift before the influence of Intel's stillborn Larrabee graphics project can be detected in its integrated graphics cores. Despite all that, TechRadar's spies inside the Intel mothership tell us to expect something a little bit special from Sandy Bridge's graphics performance. Time will tell.

Sandy Bridge release date

Intel has yet to ink in a firm release date. No doubt we'll get a better idea of the launch schedule at IDF in September. However, Intel's rough plan is to begin shipping chips to customers before the end of the year with retail sales beginning either in very late 2010 or early 2011. Look out for our full Sandy Bridge review then.

Texas Instruments has announced that it is the first company to licence ARM's 'Eagle' Cortex A series processor core, as it extends its plans for smartphones and mobile internet devices.

TI is the fourth biggest chip manufacturer in the world, and has signed up with British company ARM to use the Eagle processor for its OMAP family – primarily focused on portable devices like smartphones and MIDs.

"Building on its rich heritage of collaboration with ARM, Texas Instruments Incorporated (TI) today confirmed that it was the first company to partner with ARM in the conception and definition of the next generation ARM Cortex-A series processor core (also known as "Eagle") to be announced later this year," announced TI.

"TI intends to use the new processor to further strengthen and extend its future OMAP platform offerings.

"This engagement accelerates TI's ability to get to market early with high-performance OMAP products based on the new ARM processor core, following up on its popular OMAP 4 platform that uses the powerful Cortex-A9 processor core.

Mobile advances

"The partnership's efforts also reiterate TI's commitment to spearheading high-performance, low-power mobile advances," the release adds.

The upshot is that Texas Instruments is hoping to offer to manufacturers 'intense performance capabilities and low power consumption' by combining Eagle and the company's SmartReflex power and performance management.

"Our position as ARM's advanced lead partner for its next-generation Cortex-A series processor core underscores TI's unwavering commitment to helping customers achieve success in the competitive mobile world," said Remi El-Ouazzane, vice president, OMAP platform business unit TI.

"We are thrilled to know that our customers will be the first to leverage the new ARM processor core's far-reaching innovations via our industry-leading OMAP products.

"Successful mobile industry achievements revolve around the 'high-performance, low-power' mantra, and we believe the results of our collaborative effort echo the importance of this must-have balance."

TI and ARM have a long-standing relationship stretching back to the early nineties, and the former has shipped more than 250 million chips using the latter's architecture.

Microsoft has signed a new licensing agreement with British company ARM to use its architecture.

The software giant has had deals in place with ARM since 1997, with the companies collaborating on software and devices 'across the embedded consumer and mobile spaces'

"Microsoft is an important member of the ARM ecosystem, and has been for many years," said Mike Muller, CTO ARM.

"With this architecture license, Microsoft will be at the forefront of applying and working with ARM technology in concert with a broad range of businesses addressing multiple application areas."

Phones and embedded

Microsoft's general manager KD Hallman explained that mobile phones and embedded devices that use ARM's designs run Microsoft products.

"ARM is an important partner for Microsoft and we deliver multiple operating systems on the company's architecture, most notably Windows Embedded and Windows Phone," said KD Hallman, general manager, Microsoft.

"With closer access to the ARM technology we will be able to enhance our research and development activities for ARM-based products."

Interestingly, there has been talk of Windows 8 potentially running on the ARM architecture, with Steven Sinofsky not ruling out the possibility to TechRadar.

ARM has signed a deal with Taiwan Semiconductor Manufacturing Corp to produce next generation 20 and 28nm chips.

John Heinlein, vice president of marketing for British company ARM, announced the deal on his blog, believing that the deal with TSMC will make devices smaller and sleeker and improve battery life.

"ARM and TSMC announced a major new collaboration to help drive this kind of innovation forward for many years to come," wrote Heinlein.

Key challenges

"One of the key challenges in delivering advanced devices is achieving the performance gains we have come to expect while also achieving battery life improvements and making devices smaller and sleeker," he continued

"This collaboration is designed to help our partners achieve exactly that.

"…this agreement establishes a long term relationship between TSMC and ARM centered on the development of ARM Physical IP for TSMC's most advanced 28nm and 20nm processes, products like memory compilers and standard cell libraries that our partners use to assemble their chips."

Shaping innovation

Heinlein states that the deal is vital to continue the kinds of innovation that have shaped the first decade of this millennium.

"My latest smartphone is smaller than ever and yet boasts a high resolution still and video camera," says Heinlein.

"Also, I'm shifting more and more of my work to an ultra-thin tablet that's smaller and lighter than a full-size notebook.

"But as everyone knows, it's getting tougher and tougher to deliver that kind of innovation.

"That is exactly why today's announcement between ARM and TSMC is so important to the future of mobile and other consumer devices."

Intel has announced its best ever quarter, putting a $2.9 billion (£1.91bn) profit down to healthy PC and server markets and its own 'leading-edge' technology.

The chip giant increased profits from the last quarter by a whopping $445 (£293m) and reporting revenue of $10.8 billion (£7 billion).

The Core ranges have proven to be popular in desktops and, perhaps more importantly, the still-buoyant laptop arena, while Atom has become the key player in netbooks.

Strong demand

But corporate customers were credited with the huge profits reported, in a 34 per cent increase in revenue.

"Strong demand from corporate customers for our most advanced microprocessors helped Intel achieve the best quarter in the company's 42-year history," said Paul Otellini, Intel president and CEO.

"Our process technology lead plus compelling architectural designs increasingly differentiate Intel-based products in the marketplace.

"The PC and server segments are healthy and the demand for leading-edge technology will continue to increase for the foreseeable future."

Not bad, especially considering the company is still paying off the massive European Commission fine.

Both Intel and Qualcomm have launched new processors at this month's Computex event in Taipei.

First up was Intel, with its new Oak Trail, Tunnel Creek and Canoe Lake processor lines.

Canoe Lake was being pushed as a platform, which can allow manufacturers to produce a dual-core netbook at a super-slim 14-millimeters thick, running Intel's Pine Trail version of its Atom processor.

New smartphone chips

Intel also showcased its Tunnel Creek 'system on a chip' Atom processor for small devices running a range of operating systems, including MeeGo, Google Android or Chrome, and Windows 7.

Asus is set to be the first manufacturer to ship a pre-installed version of Intel's netbook app store, called the Asus AppStore, later this year.

Qualcomm's next gen Snapdragon chip for smartphones was also announced at Computex this week, which is a low-power 1.2GHz dual-core chip capable of handling 1080p video.

No word on release dates from Qualcomm, but TechRadar will be watching out for more news on the new Snapdragons, which we expect to see arriving in new Android, Palm, and Microsoft Windows 7 phones soon.

AMD has introduced its new Vision platforms at a launch event in Cannes today. AMD has promised full top-to-bottom 1080p HD support, promising "at least two thirds" of the video performance of rivals at the same price point.

AMD seems to be hoping that by bundling descrete graphics into the Vision platform that it will be able to undercut Intel systems on price.

The Vision branding is now split four ways and will be used across all AMD-powered laptops and desktops.

Four new platforms have been announced - Vision, Vision Premium, Vision Ultimate and Vision Black - the latter being for high-end gaming performance.

"[This is] the biggest announcement of [AMD] platforms that will be made available at one point in time...this will have a multiplier effect for our business," said Alberto Bozzo, AMD's Vice President and General Manager for Europe.

"Strong graphics is really at the core of this," added AMD's Chief Marketing Officer Nigel Dessau - pictured below.

"People are using HDMI more and more to connect PCs to screens. Vision is a single thought, a typical good, better best. So we focused on high definition, we focused on delivering a rich internet experience."

Dessau talked of making the experience of buying a PC simpler with Vision. "There are two types of users, the people who know about processors and then the processor unaware," he said. AMD estimates that just 25 million people worldwide fall into the first category, hence the company moving completely over to the simpler Vision branding.

"We're changing how we think about things in a PC. We used to say let's get the biggest engine and drive it as fast as we can."

"We have to think about how we merchandise them [PCs]. We need to make computers easier to use, we need to make them easier to buy."

AMD's newest Turion processors - along with its more powerful Phenom sibling - is to be used in the laptops and desktops.

Acer, HP, Lenovo and others have announced new kit featuring the tech. HP alone has 14 new AMD Vision products.

"We took the speeds and feeds out and focused more on the users," said Jean-Pierre Calvez of HP. We're talking about what people actually do with the computers, we're talking about creativity."

Intel has announced its Atom Z6XX series – the chip giant's first big roll of the dice for the smartphone market. The good news is that the chip looks storming in terms of performance and is very power efficient.

The bad news? Intel has named no names in terms of handset manufacturers who might deploy the new silicon, formerly codenamed Moorestown. However, it did show off an Aava Mobile reference device completely powered by Intel hardware during a launch event attended by TechRadar.

The silicon will run the Android OS as well as Intel's joint Linux venture with Nokia, MeeGo. Support for other operating systems was clearly hinted at. Given Nokia's closeness to Intel, we reckon we'll see Symbian running on it before too long.

The second-generation Atom also "scales very well up to tablets... you're going to see a number of different ways these products will be used," said Rob O'Shea, Director of Intel's EMEA Embedded Group, as he presented the key specs of the new device.

Crucially, Intel is citing a 50 times power reduction – equating to a 10 day standby time – over the first generation of the Menlow UMPC Atom platform.

Intel was keen to show this with a real-time power consumption demo, shown here. The old Menlow Atom platform is the red line, while the new Moorestown platform is the blue line - both are measurements taken at full stretch. The barely visible green line is Moorestown at idle power.

Intel also demonstrated three-way video conferencing running live on the hardware (encoding one as well as decoding two other streams), as well as Quake 3 and 1080p HD video decoding - the device can encode 720p.

"With these kind of power reductions, we are in the smartphone zone. We are in the game," said Pankaj Kedia, Intel Director of Mobile Internet Devices. We'll bring you more from Pankaj Kedia in a separate piece on TechRadar.

Comparisons to other handsets

The smartphone version of the chip will reach 1.5GHz, while a second, tablet-orientated version will ship for tablets.Some graphs were shown comparing the performance of the new Atom to the ARM Cortex-A8 and other unidentified mobile handsets.

While these graphs were convincingly in the Atom's favour, it was unfortunate that the Cortex-A8 looked at was only clocked at 600GHz and the handsets were unidentified - worth taking with a pinch of salt. Intel also showed graphs claiming a 3-4x JavaScript browsing speed improvement over competitors, though there are so many variables within this it's hard to take the numbers that seriously until we see shipping devices.

The 140 million transistor SoC (System On Chip) component – is 45nm technology, although Intel was openly looking ahead to producing Atom using the 32nm and 22nm processes.

Intel believes its key advantage is that its architecture is already well established. "It's a computer that enables voice," Kedia said of Intel's hardware, "[It's] the [level] of experience you expect to find on a PC."

"If you can deliver great graphics and video, you can scale that up into very slim tablets. We can design where we have to have that discipline up."

Just to be clear, Moorestown is the platform, As well as the Z6XX variant of the Atom (codenamed Lincroft SoC) also controlling graphics memory and display, the platform includes a Platform Controller Hub (MP20, codenamed Langwell). The platform also includes wireless and other hardware from the likes of Freescale, Ericsson and Marvell, though the exact implementation of this will presumably depend on the handset manufacturer.

AMD's Leslie Sobon believes that the desktop PC is due a resurgence, and is hoping that the company's Leo and Dorado platforms and the six-core Thuban processor can give the industry a shot in the arm.

With laptops and desktops now dominating sales, you would be forgiven for thinking that the desktop is in terminal decline.

However, Sobon, AMD's vice president of marketing, insists that there is life in the old desktop dog yet.

Hanging in

"As much as people keep talking about the demise of desktops they're hanging in there," Sobon told TechRadar.

"The market is on our side from everything that we've seen. There is still cool technology coming…and enthusiasts will always keep it alive so it's not going to die."

AMD's high-profile Thuban processors, combined with the mainstream Dorado and higher-end Leo platforms are arriving, and Sobon believes that this brings huge benefits.

"We've got two new platforms that we are launching - the first one is Dorado which is clearly for the mainstream – it's dual, triple and quad, both discrete and UMA configurations, but it's really entry on up," she said

"Leo sits at the top end: our six core desktop product that's really for the hardcore gamer or the video enthusiasts that are editing and creating movies.

"These groups want either the headroom, because they feel the games are going to get there, or with video to take advantage of all the cores right now."

Budget friendly

AMD are keen to continue their sensible pricing strategy – not breaking the bank for enthusiasts and gamers.

"This six core product is going to be very affordable – you can see it in PCs at under $1000 so we're going to keep our mantra of 'best price performance'," added Sobon.

"So it's going to be absolutely accessible to the enthusiast community who want to buy a finished PC or, of course, build their own."

AMD, the PC processor industry's perennial second stringer, is tooling up to release its long awaited CPU-GPU "Fusion" processor.

It has all the makings of an Intel killer, particularly in mobile trim for laptop PCs.

Codenamed Llano and due out early next year, key advantages include a single-die fusion architecture and graphics power an order of magnitude greater than any previous integrated solution.

About time, too. While Intel rolls out advanced new PC processor architectures on a seemingly weekly basis, the current culmination of which is a six-core monster, AMD is almost nowhere to be seen.

Arguably, it hasn't released a properly new processor since 2003.

That's about to change. The fight back begins later this month with Thuban, AMD's six-core effort. However, Thuban is just a six-core rehash of AMD's current processor technology. Interesting addition to the meaty mid-range CPU market though it may well be, it won't worry Intel.

Instead, it will be Llano that marks AMD's real renaissance and the beginning of a danger period for Intel. AMD has been trickle-charging us with info on Llano in recent months.

Turns out it's not quite the chip we were expecting. In some ways it's actually a disappointment. But as an overall package, it's shaping up to be potentially lethal.

Crucially, Llano combines a conventional PC processor and a full-function graphics core in a single slice of silicon. Intel, of course, already has a CPU-GPU hybrid processor on sale in the form of its Arrandale and Clarkdale processors.

Strange branding

They're sold variously as Core i3, i5 and i7 processors depending on the target form factor, price segment and apparently which way the wind is blowing. There's little logic to Intel's current PC processor branding scheme.

More importantly, Intel's CPU-GPU chips are not full-on fusion products. Crack open the CPU package (highly inadvisable if you want to keep using it) and you'll find not one but two individual processor dies.

That's Intel's way of getting fusion to market faster and with fewer risks. But it's also architecturally suboptimal. Enter therefore Llano, the real single-die fusion deal and with it the promise of that rarest of things for AMD - a competitive advantage.

First up is Llano's intriguing integrated graphics core. It's absolutely huge. Exactly how huge in terms of the all-important stream processor count we can't say for sure. AMD hasn't divulged the hard numbers.

However, AMD has teased us with a few photographs of Llano which in turn reveal that the graphics core consumes nigh on 50 per cent of the entire die.

We also know that Llano will be built on AMD's upcoming 32nm chip production process and will enjoy a total transistor budget around the one billion mark.

Put those facts together and you're looking at an integrated graphics solution with a probable stream processor count somewhere north of 400 units. Not all that impressive in the context of AMD's monstrous 1,600-stream-processor-strong desktop GPU, the Radeon HD 5870. But remember, AMD's fastest current integrated graphics core sports just 40 stream processors.

Admittedly, there are doubts regarding Llano's ability to feed that graphics core with data. GPUs are extremely data hungry and it's not yet clear whether the CPU and GPU parts will share a single memory bus and if so what that bus will look like.

As for the conventional CPU half of Llano, it's based on AMD's current Stars processor architecture. Four cores, each with 1MB of L2 cache and a few tweaks to what is a rather ancient architecture will be your lot.

That's a little bit of a bummer given that AMD had originally planned to use a brand new CPU architecture for its first Fusion product.

Moreover, there's nothing Llano has or does that will upset the status quo on the desktop. As a CPU it will be unremarkable. Meanwhile, any desktop graphics card worth its salt with give it thumping for sheer 3D rendering grunt.

Laptops and GPGPU

Shift the emphasis to mobile computing, however, and suddenly Llano looks a lot more clever. What you have is a highly integrated solution based on cutting edge 32nm chip tech with thoroughly adequate quad-core performance and the added bonus of some serious vector throughput. And all from a power efficient chip suitable for very thin and very light portables.

What we're also hinting at here is the much-hyped but little realised notion of running general purpose software on a graphics chip. Known as GPGPU for short, it's often claimed to deliver a massive leap in performance for applications that major on floating point calculations and lend themselves to the massively parallel nature of graphics chips.

Thanks to the arrival of the compute shader in DX11 along with several other industry-wide efforts, GPGPU is expected to finally gain traction over the next 12 months or so. Just in time for the arrival of Llano. If that does happen, Intel will almost definitely have no answer.

What about Sandy Bridge?

For starters, Intel has a poor track record in graphics and has yet to prove it can build a really decent 3D core. What's more, die shots of Intel's upcoming Sandy Bridge processors, due next year and slated to take on Llano, reveal two things.

The good news is that Sandy Bridge is going monolithic: the graphics features will be on-die rather than merely in-package. Less impressive is the size of the graphics core. It's tiny compared to Llano's.

In short, Llano looks like a much more balanced architecture. In fact, it looks so good it's not hard to imagine a certain fruit-theme maker of computing devices sizing it up. Llano power for the next MacBook Air? It would make an awful lot of sense.

Despite saying that "Intel is very supportive of Windows," James Reinders, Chief Evangelist of Software Tools at Intel, criticises Microsoft roundly in an interview with TechRadar.

Why? He says it's taken too long for the software giant to make Windows run well on Atom and to make a success of Intel's UMPC and MID ideas.

There are new tools on the way from Intel this year (as well as a new layer in Windows 7, the concurrency runtime) to help programmers do the tricky parallel programming that you need to take advantage of multicore – but that's not enough to solve all the problems, especially for Atom.

Five years ago, Reinders still had to work on convincing developers that PCs weren't going to keep on getting faster; "People would ask me 'isn't Intel just going invent a faster transistor?'

"Now I don't have to explain it anymore." But while he hopes that major app vendors like Adobe will take full advantage of multi-core systems, "I think we have a few years before people say it's really happening."

Atom's multicore future

Even Atom will go multicore, in time. "It will be a little bit slower initially because of the power constraints but as time marches on we will solve the power problem." That's important because until then, he agrees that "netbooks will definitely hold us back" by making developers less interested in writing parallel code that won't run on them.

Today games developers do the most with multi-core, he says; "There are games you can buy that do more physics simulation than they probably did on the Manhattan project." But he predicts those techniques will move quickly into the user interface for other apps.

"I think we're going to get hugely addicted to using compute power for human interface - head tracking and so on". Microsoft Office already uses multiple threads for different tasks; "There's parallelism in places you don't expect," says Reinders.

"Word does spell checking and grammar checking in the background and if you're on a multi-core system you'll see those little squiggles appear under the words much more quickly." He's excited about the way IE9 will use a second core to speed up JavaScript and predicts that "HTML 5 is going to drive a lot of parallelism in future."

Why so long for Windows on Atom?

He doesn't claim any inside information about Windows 8, but expects it to do more parallelism. "I think the OS will change. I know nothing but I can anticipate them changing [task] scheduling and improving some of things they do to handle multi-core." He predicts that confidently because, he says, "It has to be a priority."

Partly that's because although the new concurrency runtime makes it easier to make one application speed up by taking advantage of multiple cores, it won't help if multiple apps are trying to do that. "If you run three [instances], they will try to oversubscribe the machine."

"Microsoft hasn't been quite as aggressive as we might have hoped at supporting Atom, especially in the embedded space and that's why we came up with our platform Moblin - which is now MeeGo. Intel is all about platform choice, choice of operating system and so on, and we believe in the opportunity of embedded very strongly.

Windows 7 "doesn't go the places we think Atom will go"

"Some of their Windows offerings are great now, but Moblin started a number of years ago when we didn't see Windows in that space at all. We're thrilled to death to see user mode scheduling in Windows 7 but the progress of Windows 7 still limited - it doesn't go all the places we think Atom will go."

Those places include smartphones, MIDs, tablets and in-car systems, for a start, and Android – or the version of Mac OS in the iPad – just isn't enough in his view. "We feel people want an operating system that is more powerful on these devices.

Pushing Moblin is definitely about getting more choice it that space." Intel partnered with Nokia to turn Moblin into the more smartphone-friendly MeeGo, but Intel doesn't always come out on top in the partnership; Reinders predicts Nokia will get MeeGo devices to market before Intel can. He admits; "It's a challenge for us.

Intel has previewed its upcoming 'Tunnel Creek' System-on-Chip (SoC) tech for in-vehicle-infotainment systems for cars. Interestingly, the demo - on a vehicle designed by Chinese car maker HawTai and based on the Queensbay platform - was running MeeGo, Intel's now joint venture OS with Nokia.

The forthcoming SoC hardware features an Intel Atom processor core that will directly connect to other third-party devices via the PCI Express standard, saving on cost. Queensbay is, essentially, a later version of the company's Menlow platform.

The Tunnel Creek SoC combines the processor core, memory controller hub, graphics engine and video engine into one chip and because of the PCI Express compatibility could link to other technologies such as Nvidia's Ion graphics chip. The hardware could also be used for other applications such as IP telephony, says Intel.

Dian Ming, vice chairman of HawTai Automotive, was predictably enthusiastic about the new hardware. "It saves us application development costs, and enables new services to be introduced quickly with high reliability."

"With an infotainment solution that utilises the Intel Atom processor, we are leveraging the well-established and latest internet technologies, and re-using existing software that has been developed on [the] MeeGo based Linux platform," said Mr Wang.

Frugal power use

Energy efficiency is another key theme of this IDF. Intel Chief Technology Officer and managing director of Intel Labs, Justin Rattner, discussed how smarter technology can reduce and better manage energy consumption.

"Consumer empowerment is critical," said Rattner. "If we can make energy more personalised with real-time information and offer visual tools that engage entire communities, it will lead to valuable changes in behavior and save staggering amounts of energy."

Intel researchers have invented a new wireless device to make the collection of energy data easy and inexpensive for consumers. The experimental sensor needs to be plugged into your home's electrical wiring to measure and wirelessly report the power consumption of each electrical load.

Intel has also been talking up the "connected computing experience" where all devices share information (if only).

"With an additional 1 billion connected computing users by 2015 and with more types of devices there is value in providing a common experience between the devices," said David (Dadi) Perlmutter, executive vice president and co-general manager, Intel Architecture Group.

"Intel architecture delivers the right combination of performance and power that provides the foundation across all computing devices creating a virtual continuum of computing to enable this common user experience."

Dual-core Atom processors for netbooks could be coming soon from Intel, according to the company's president Paul Otellini.

Intel has had its best start to the year ever, with a huge increase in profit showing that the economic difficulties have not stopped people investing in their computers.

Speaking as the results were announced, Otellini said: "the next innovation coming out on Atom is dual core, which comes out in the second quarter."

With dual-core Atoms already being used in small media computers or nettops, to merit such an announcement it seems likely that the forthcoming chips are for netbooks.

Quarter masters

Intel announced a 400 percent increase in year-on-year quarterly profit, raking in $2.4 billion (£1.55bn) and producing a profit of 43 cents a share – significantly more than analyst predictions.

The company cited that it was huge growth in its mobile microprocessor revenue that was responsible for the good news.

Of course, Intel's Atom chips remain dominant in the burgeoning netbook market, and the company has traditionally been very strong in laptops, despite competition from rival AMD.

Intel is also looking forward to some key additions to its offering in the coming months, including the Moorestown platform and the dual-core Atoms that have got the mobile computing world humming.

Intel's next generation of Atom processors will not only bring higher clockspeeds but also support for DDR3 memory.

With the Atom N470, N475 and N455 arriving in the coming months, according to Fudzilla faster Atoms are planned for the same time period.

That includes the N475 and N455, both with DDR3 support and the more power-hungry 1.8GHz D525 which can deal with either DDR2 or DDR3, something sure to be popular with OEM's.

Fitter, happier, more productive

The 'D' range of Atoms are intended for desktop devices, whereas the N series are designed for laptops and take significantly less power.

DDR3 SDRAM, to give it its full name, is significantly faster that the older DDR2 RAM, and brings significant performance boosts.

The next generation of Atom devices will start to appear soon after the chips hit the market, and the performance level between netbooks and laptops continues to fall.

Wouldn't it be great if money didn't matter? In that altogether salubrious scenario, picking a PC processor would be quick and painless. After all, Intel makes undeniably the best money-no-object chip known to man.

Run the Core i7 975 Extreme Edition through any imaginable battery of benchmarks and it will return superior results to every other CPU currently available every time. The slight snag is the 975's punitive pricing: it will lighten your wallet to the tune of nearly £800.

To that figure, you then have to add hundreds more for a motherboard, a hefty helping of system memory, a decent graphics card and various items of PC paraphernalia. It all mounts up very quickly. Back in the real world, therefore, money does matter.

In turn, that makes CPU selection rather more complicated. Even if you do stick with Intel, for example, there are currently no fewer than three distinct sockets to choose from, each supporting a small army of processor models. Plus with value for money in mind you'd be unwise to disregard AMD.

It may not be able to compete with Intel on raw computational horsepower at the moment, but AMD has pulled out the stops on pricing. It has some incredible bang for buck on offer. Of course, the age-old AMD or Intel question is just one of many conundrums facing the intrepid CPU buyer.

Increasingly one must choose between maximising operating frequencies or core counts. If you're on a budget, so the conventional wisdom goes, you can't have both. That certainly seems to be the case if you make a comparison of processor models based on advertised clockspeeds.

Throw overclocking into the mix, however, and the pecking order changes rapidly. There are some real giant-killer CPUs out there if you're willing to have a go yourself.

Back to the future

Next, there's the question of future-proofing. One of the PC's greatest strengths has always been its ability to reinvent itself through constant technological progress and innovation. Nevertheless, some CPUs and their associated sockets and platforms are longer for this world than others.

AMD has a better track record than Intel for maintaining both backward and forward compatibility when it comes to this area. This is the kind of detail that might just swing your decision when much else is equal. If we're talking platform comparisons, there are a number of further factors to consider.

At first glance, two processors might seem closely matched in terms of price and performance. But add the supporting platform to the equation and a yawning gap can appear. Motherboards compatible with Intel's latest CPUs, for example, are still quite pricey.

Likewise, a cheap Core i7 chip is a false economy if you can't afford enough triple-channel memory to do it justice. As ever, it's horses for courses. For that reason, we've reduced the bubbling mass of CPU models available to just four hard-boiled devices. Each represents a respective best in class in the categories of value, future-proofing and overclocking, with the fourth and final our all-round top chip.

Clocks vs cores

Let's put the thought of prizes to one side for now and attack the first major conundrum, that of clocks and cores. If you can't have the best of both, which should take preference?

On the one hand, not all application types are keeping pace with the reality of multi-core hardware. Web browsing and gaming are the two most obvious examples of software types that have remained at least somewhat resistant to multi-threading efforts. Until the challenge of coding such multi-threaded software is overcome, multi-core processors will not fulfil their potential.

On the other hand, there's no doubting that the PC industry as a whole has effectively bet the farm on threaded software and multicore processor architectures. Wind back the clock to around 2004 and it was becoming increasingly apparent that the clockspeed-centric approach to ever-greater performance had hit a wall, on top of which was a large neon sign flashing '4GHz'.

But if the quest for ever-higher clockspeeds had come unstuck, advancements in integrated circuit production technology were allowing engineers to squeeze ever larger numbers of transistors into computer silicon chips. The only way to make the most of these increasing transistor budgets and therefore keep performance moving forward was to add more cores.

Thus we had what Intel now calls its 'right-hand turn'; the industry changed tack in favour of the current multi-core architectures.

The reign of multi-core

Most computationally demanding applications, including image rendering and media encoding, are already highly threaded and multi-core friendly. That will only become truer in future. Indeed, the more cores your CPU packs, the more you will find its performance potential is increasingly unlocked over the next few years as software developers hone their threading prowess.

Gaming is a good example here. Thanks to the recent release of Windows 7 and improved support in the new DirectX 11 API, games should be able to exploit multi-core chips much more effectively. What's more, the more cores you have, the better your PC will be for multi-tasking. These days, who doesn't have a plethora of apps running simultaneously?

As a general rule, then, we reckon the more cores and threads your processor can pony up the better. Consequently, quad-core is what you should be aiming for. That's especially true given that four cores can now be had for well under £100.

Admittedly, AMD has confused the issue somewhat with its triple-core X3 processors. Indeed, in some instances, a triple-core processor with a healthy helping of cache memory will outperform a similarly priced quad-core processor with cut-down cache. But such scenarios will become rarer and rarer going forward.

The final and clinching argument is that while overclocking can be used to increase operating frequency, adding cores to your CPU tends to be much more difficult – if not always impossible.

Intel vs AMD

Now that we've established quad-core as the basic configuration of choice, should it be four Intel cores or four from AMD?

Well, Intel will currently sell you quad-core chips under the Core 2, Core i5 and Core i7 brands while AMD will supply you with both Phenom II and Athlon II CPUs in quad-core trim.

The easiest processor to discard is Intel's elderly Core 2. That's not because it's a weak performer or represents poor value – it's still a nice chip.

No, the problem is the aging LGA 775 socket that comes with it. It's a dead end and is soon to be killed off. If you already have an LGA 775 system and seek only to upgrade your CPU, the Core 2 is fine. But LGA 775 is a no-no for new PC builds. It has no future.

On the broader AMD vs Intel question, a large part of the answer comes down to cost. The more constrained your budget, the more AMD's processors make sense. The key point here is to look beyond the headline price of a given processor.

DECISIONS, DECISIONS: The decision of Intel over AMD is not as straightforward as you might think

You might, for instance, compare AMD's Phenom II X4 965 Black Edition chip to Intel's new Core i5 750, two processors that compete in the sub-£150 market. For the most part, this pairing delivers very similar performance, save for gaming where Intel has a clear edge. Add to that the fact that the Core i5 can occasionally be had for a few quid less and you might think that it's the obvious choice.

However, factor in motherboard prices and the winner is much less clear. Currently, only Intel's P55 chipset is compatible with the LGA 1156 socket required for Core i5 processors. You'll struggle to find a P55 motherboard for less than £80. By contrast, £45 is enough to secure a motherboard fit for the Phenom II.

Making matters worse for the Intel chip is the fact that it requires pricey DDR3 memory. For the AMD CPU you can opt for either DDR3 or cheaper DDR2 memory through your choice of the AM3 or AM2+ sockets respectively, both of which are compatible with Phenom II and Athlon II processors. This allows you to further cut costs, though you should remember that choosing the older AM2+ socket could limit your options for CPU upgrades in the future.

It wouldn't surprise us if AMD's upcoming six-core processor was only compatible with AM3 motherboards.

Intel makes things even tougher when it comes to choosing between sockets. With its new Core i5 and Core i7 family of processors it has introduced two incompatible sockets, LGA 1156 and LGA 1366. On paper, they form the basis of mainstream and high-end platforms respectively.

Unfortunately, Intel in its wisdom has chosen not to align its processor branding with the realities of the underlying hardware. So, while the Core i5 chip is indeed reserved for the LGA 1156 socket, Intel sells Core i7 chips in both formats, denoted in Intel's new product nomenclature as the Core i7 800 and 900 series respectively.

Significantly, these two flavours of Core i7 are distinctly different in terms of underlying architecture. Firstly, the 900 series chips and therefore all LGA 1366 boards sport a triple-channel memory interface. In other words, you have to have three rather than two sticks of DDR3 memory in order to achieve the maximum bandwidth.

Secondly, all chips on the LGA 1156 platform (that's all Core i5 processors and the Core i7 800 series CPUs) have 16-lane PCI Express controllers integrated into the processor die. Compared to the LGA 1366 platform – and indeed many AMD-based platforms, which often provide 32 or more lanes – this places a cap on the number of high-performance PCI Express peripherals, such as graphics cards, that can be attached.

For your average PC user that's hardly a crushing limitation, but it's worth bearing in mind should you wish to run multiple video cards or perhaps use a GPU as a general-purpose coprocessor in the future. Such high-end configurations will not necessarily be impossible, of course but there will certainly be some limitations that don't apply to those platforms that feature 32 or more PCI Express lanes.

The final issue concerns futureproofing and upgrade paths. LGA 1366 will be Intel's high-end socket for the foreseeable future. Early next year Intel will unleash its new six-core monster, codenamed Gulftown. It will only be available in LGA 1366 trim. Hence, with Intel platforms you can no longer buy a cheapish motherboard and drop in a high-end CPU later. You need to invest in the full platform.

Right now, however, there's actually remarkably little difference in terms of performance between the various Core i7 processors operating on the LGA 1156 and LGA 1366 sockets. In fact, thanks to an aggressive implementation of Intel's automatic overclocking feature (which is known as Turbo Boost), LGA 1156 can sometimes be faster.

In other words, unless you plan to upgrade to a six-core processor chip next year, there is probably little sense in paying extra for the pricier LGA 1366 processors and motherboards at the moment. Your current needs will be easily fulfilled by a processor on a cheaper LGA 1156 socket.

Prioritising features

Finally on Intel processors, it's worth noting that the lack of HyperThreading on the Core i5 700 series compromises performance in highly threaded apps by as much as 25 per cent.

HyperThreading is Intel's symmetric multi-threading technology. It allows a single core to crunch two software threads at the same time. Hence, quad-core Core i7 processors make eight logical processors available to a PC's OS.

HYPERTHREADING: The Core i7 has up to 8 cores available, four of which are virtual cores

As for AMD's Phenom II and Athlon II chips, there are fewer foibles to grapple with. Your choice essentially boils down to cores, clocks and cache memory. Both processor families are available in dual, triple, and quad-core configurations running at a wide range of clockspeeds.

Regarding cache memory, the key difference is level three (L3) cache: Phenom IIs have it, Athlon IIs don't. The lack of L3 cache hurts the Athlon II's performance compared to otherwise similar Phenom II chips to the tune of 10 to 15 per cent. It's significant, but certainly not a deal breaker.

That's because the underlying architectures of AMD's two key processor families are essentially the same. Combined with AMD's far more flexible platforms in terms of socket compatibility, it makes for a much more straightforward range of CPUs than Intel's increasingly baffling chips.

Overclocking issues

All of which leaves us with one final issue to address: overclocking. In the past, trying to squeeze extra performance out of a PC processor was not only dangerous but also often futile. For starters, processors and motherboards tended to lack fail-safe circuitry that protected them from the effects of running at increased frequencies and voltages. Torching your pricey processor was a genuine risk.

At the same time, the amount of headroom on offer was often rather modest. Five or six years ago, a 10 per cent overclock was a decent result. Today, all that has changed. Not only is overclocking much safer than before, the results can be truly spectacular. It's not unusual for Intel processors to overclock by as much as 1.5GHz. That kind of boost can translate into a huge performance increase of 50 per cent or more.

Intriguingly, however, it tends to be processors in the middle to lower order of any given processor family that offer the best results. Put simply, processor architectures usually have a frequency ceiling beyond which they won't operate. This applies almost regardless of their official operating speed.

For Intel's Core i7 chips, that limit is often around or just above the 4GHz mark. Take the Core i7 920 processor, for example. Officially it's a 2.66GHz chip and yours for around £200 – but when overclocked (using standard voltages), it's usually capable of stable frequencies of around 4GHz to 4.1GHz.

However, the 3.33GHz, £750 Core i7 975 only increases that headroom to 4.3GHz or so. That's over three times the price for a speed advantage of just five per cent.

Broadly speaking, AMD's chips tend to be a little less overclockable and top out at approximately 3.7GHz to 3.8GHz. However, the same philosophy applies. The higher up the chip range you go, the less headroom you get.

The lesson here is that if you are willing to dabble in a little overclocking, you can enjoy the very best processor performance either AMD or Intel can currently offer, but at a mere fraction of the price. That's got to be worth a try.

Wouldn't it be great if money didn't matter? In that altogether salubrious scenario, picking a PC processor would be quick and painless. After all, Intel makes undeniably the best money-no-object chip known to man.

Run the Core i7 975 Extreme Edition through any imaginable battery of benchmarks and it will return superior results to every other CPU currently available every time. The slight snag is the 975's punitive pricing: it will lighten your wallet to the tune of nearly £800.

To that figure, you then have to add hundreds more for a motherboard, a hefty helping of system memory, a decent graphics card and various items of PC paraphernalia. It all mounts up very quickly. Back in the real world, therefore, money does matter.

In turn, that makes CPU selection rather more complicated. Even if you do stick with Intel, for example, there are currently no fewer than three distinct sockets to choose from, each supporting a small army of processor models. Plus with value for money in mind you'd be unwise to disregard AMD.

It may not be able to compete with Intel on raw computational horsepower at the moment, but AMD has pulled out the stops on pricing. It has some incredible bang for buck on offer. Of course, the age-old AMD or Intel question is just one of many conundrums facing the intrepid CPU buyer.

Increasingly one must choose between maximising operating frequencies or core counts. If you're on a budget, so the conventional wisdom goes, you can't have both. That certainly seems to be the case if you make a comparison of processor models based on advertised clockspeeds.

Throw overclocking into the mix, however, and the pecking order changes rapidly. There are some real giant-killer CPUs out there if you're willing to have a go yourself.

Back to the future

Next, there's the question of future-proofing. One of the PC's greatest strengths has always been its ability to reinvent itself through constant technological progress and innovation. Nevertheless, some CPUs and their associated sockets and platforms are longer for this world than others.

AMD has a better track record than Intel for maintaining both backward and forward compatibility when it comes to this area. This is the kind of detail that might just swing your decision when much else is equal. If we're talking platform comparisons, there are a number of further factors to consider.

At first glance, two processors might seem closely matched in terms of price and performance. But add the supporting platform to the equation and a yawning gap can appear. Motherboards compatible with Intel's latest CPUs, for example, are still quite pricey.

Likewise, a cheap Core i7 chip is a false economy if you can't afford enough triple-channel memory to do it justice. As ever, it's horses for courses. For that reason, we've reduced the bubbling mass of CPU models available to just four hard-boiled devices. Each represents a respective best in class in the categories of value, future-proofing and overclocking, with the fourth and final our all-round top chip.

Clocks vs cores

Let's put the thought of prizes to one side for now and attack the first major conundrum, that of clocks and cores. If you can't have the best of both, which should take preference?

On the one hand, not all application types are keeping pace with the reality of multi-core hardware. Web browsing and gaming are the two most obvious examples of software types that have remained at least somewhat resistant to multi-threading efforts. Until the challenge of coding such multi-threaded software is overcome, multi-core processors will not fulfil their potential.

On the other hand, there's no doubting that the PC industry as a whole has effectively bet the farm on threaded software and multicore processor architectures. Wind back the clock to around 2004 and it was becoming increasingly apparent that the clockspeed-centric approach to ever-greater performance had hit a wall, on top of which was a large neon sign flashing '4GHz'.

But if the quest for ever-higher clockspeeds had come unstuck, advancements in integrated circuit production technology were allowing engineers to squeeze ever larger numbers of transistors into computer silicon chips. The only way to make the most of these increasing transistor budgets and therefore keep performance moving forward was to add more cores.

Thus we had what Intel now calls its 'right-hand turn'; the industry changed tack in favour of the current multi-core architectures.

The reign of multi-core

Most computationally demanding applications, including image rendering and media encoding, are already highly threaded and multi-core friendly. That will only become truer in future. Indeed, the more cores your CPU packs, the more you will find its performance potential is increasingly unlocked over the next few years as software developers hone their threading prowess.

Gaming is a good example here. Thanks to the recent release of Windows 7 and improved support in the new DirectX 11 API, games should be able to exploit multi-core chips much more effectively. What's more, the more cores you have, the better your PC will be for multi-tasking. These days, who doesn't have a plethora of apps running simultaneously?

As a general rule, then, we reckon the more cores and threads your processor can pony up the better. Consequently, quad-core is what you should be aiming for. That's especially true given that four cores can now be had for well under £100.

Admittedly, AMD has confused the issue somewhat with its triple-core X3 processors. Indeed, in some instances, a triple-core processor with a healthy helping of cache memory will outperform a similarly priced quad-core processor with cut-down cache. But such scenarios will become rarer and rarer going forward.

The final and clinching argument is that while overclocking can be used to increase operating frequency, adding cores to your CPU tends to be much more difficult – if not always impossible.

Intel vs AMD

Now that we've established quad-core as the basic configuration of choice, should it be four Intel cores or four from AMD?

Well, Intel will currently sell you quad-core chips under the Core 2, Core i5 and Core i7 brands while AMD will supply you with both Phenom II and Athlon II CPUs in quad-core trim.

The easiest processor to discard is Intel's elderly Core 2. That's not because it's a weak performer or represents poor value – it's still a nice chip.

No, the problem is the aging LGA 775 socket that comes with it. It's a dead end and is soon to be killed off. If you already have an LGA 775 system and seek only to upgrade your CPU, the Core 2 is fine. But LGA 775 is a no-no for new PC builds. It has no future.

On the broader AMD vs Intel question, a large part of the answer comes down to cost. The more constrained your budget, the more AMD's processors make sense. The key point here is to look beyond the headline price of a given processor.

DECISIONS, DECISIONS: The decision of Intel over AMD is not as straightforward as you might think

You might, for instance, compare AMD's Phenom II X4 965 Black Edition chip to Intel's new Core i5 750, two processors that compete in the sub-£150 market. For the most part, this pairing delivers very similar performance, save for gaming where Intel has a clear edge. Add to that the fact that the Core i5 can occasionally be had for a few quid less and you might think that it's the obvious choice.

However, factor in motherboard prices and the winner is much less clear. Currently, only Intel's P55 chipset is compatible with the LGA 1156 socket required for Core i5 processors. You'll struggle to find a P55 motherboard for less than £80. By contrast, £45 is enough to secure a motherboard fit for the Phenom II.

Making matters worse for the Intel chip is the fact that it requires pricey DDR3 memory. For the AMD CPU you can opt for either DDR3 or cheaper DDR2 memory through your choice of the AM3 or AM2+ sockets respectively, both of which are compatible with Phenom II and Athlon II processors. This allows you to further cut costs, though you should remember that choosing the older AM2+ socket could limit your options for CPU upgrades in the future.

It wouldn't surprise us if AMD's upcoming six-core processor was only compatible with AM3 motherboards.

Intel makes things even tougher when it comes to choosing between sockets. With its new Core i5 and Core i7 family of processors it has introduced two incompatible sockets, LGA 1156 and LGA 1366. On paper, they form the basis of mainstream and high-end platforms respectively.

Unfortunately, Intel in its wisdom has chosen not to align its processor branding with the realities of the underlying hardware. So, while the Core i5 chip is indeed reserved for the LGA 1156 socket, Intel sells Core i7 chips in both formats, denoted in Intel's new product nomenclature as the Core i7 800 and 900 series respectively.

Significantly, these two flavours of Core i7 are distinctly different in terms of underlying architecture. Firstly, the 900 series chips and therefore all LGA 1366 boards sport a triple-channel memory interface. In other words, you have to have three rather than two sticks of DDR3 memory in order to achieve the maximum bandwidth.

Secondly, all chips on the LGA 1156 platform (that's all Core i5 processors and the Core i7 800 series CPUs) have 16-lane PCI Express controllers integrated into the processor die. Compared to the LGA 1366 platform – and indeed many AMD-based platforms, which often provide 32 or more lanes – this places a cap on the number of high-performance PCI Express peripherals, such as graphics cards, that can be attached.

For your average PC user that's hardly a crushing limitation, but it's worth bearing in mind should you wish to run multiple video cards or perhaps use a GPU as a general-purpose coprocessor in the future. Such high-end configurations will not necessarily be impossible, of course but there will certainly be some limitations that don't apply to those platforms that feature 32 or more PCI Express lanes.

The final issue concerns futureproofing and upgrade paths. LGA 1366 will be Intel's high-end socket for the foreseeable future. Early next year Intel will unleash its new six-core monster, codenamed Gulftown. It will only be available in LGA 1366 trim. Hence, with Intel platforms you can no longer buy a cheapish motherboard and drop in a high-end CPU later. You need to invest in the full platform.

Right now, however, there's actually remarkably little difference in terms of performance between the various Core i7 processors operating on the LGA 1156 and LGA 1366 sockets. In fact, thanks to an aggressive implementation of Intel's automatic overclocking feature (which is known as Turbo Boost), LGA 1156 can sometimes be faster.

In other words, unless you plan to upgrade to a six-core processor chip next year, there is probably little sense in paying extra for the pricier LGA 1366 processors and motherboards at the moment. Your current needs will be easily fulfilled by a processor on a cheaper LGA 1156 socket.

Prioritising features

Finally on Intel processors, it's worth noting that the lack of HyperThreading on the Core i5 700 series compromises performance in highly threaded apps by as much as 25 per cent.

HyperThreading is Intel's symmetric multi-threading technology. It allows a single core to crunch two software threads at the same time. Hence, quad-core Core i7 processors make eight logical processors available to a PC's OS.

HYPERTHREADING: The Core i7 has up to 8 cores available, four of which are virtual cores

As for AMD's Phenom II and Athlon II chips, there are fewer foibles to grapple with. Your choice essentially boils down to cores, clocks and cache memory. Both processor families are available in dual, triple, and quad-core configurations running at a wide range of clockspeeds.

Regarding cache memory, the key difference is level three (L3) cache: Phenom IIs have it, Athlon IIs don't. The lack of L3 cache hurts the Athlon II's performance compared to otherwise similar Phenom II chips to the tune of 10 to 15 per cent. It's significant, but certainly not a deal breaker.

That's because the underlying architectures of AMD's two key processor families are essentially the same. Combined with AMD's far more flexible platforms in terms of socket compatibility, it makes for a much more straightforward range of CPUs than Intel's increasingly baffling chips.

Overclocking issues

All of which leaves us with one final issue to address: overclocking. In the past, trying to squeeze extra performance out of a PC processor was not only dangerous but also often futile. For starters, processors and motherboards tended to lack fail-safe circuitry that protected them from the effects of running at increased frequencies and voltages. Torching your pricey processor was a genuine risk.

At the same time, the amount of headroom on offer was often rather modest. Five or six years ago, a 10 per cent overclock was a decent result. Today, all that has changed. Not only is overclocking much safer than before, the results can be truly spectacular. It's not unusual for Intel processors to overclock by as much as 1.5GHz. That kind of boost can translate into a huge performance increase of 50 per cent or more.

Intriguingly, however, it tends to be processors in the middle to lower order of any given processor family that offer the best results. Put simply, processor architectures usually have a frequency ceiling beyond which they won't operate. This applies almost regardless of their official operating speed.

For Intel's Core i7 chips, that limit is often around or just above the 4GHz mark. Take the Core i7 920 processor, for example. Officially it's a 2.66GHz chip and yours for around £200 – but when overclocked (using standard voltages), it's usually capable of stable frequencies of around 4GHz to 4.1GHz.

However, the 3.33GHz, £750 Core i7 975 only increases that headroom to 4.3GHz or so. That's over three times the price for a speed advantage of just five per cent.

Broadly speaking, AMD's chips tend to be a little less overclockable and top out at approximately 3.7GHz to 3.8GHz. However, the same philosophy applies. The higher up the chip range you go, the less headroom you get.

The lesson here is that if you are willing to dabble in a little overclocking, you can enjoy the very best processor performance either AMD or Intel can currently offer, but at a mere fraction of the price. That's got to be worth a try.

Wouldn't it be great if money didn't matter? In that altogether salubrious scenario, picking a PC processor would be quick and painless. After all, Intel makes undeniably the best money-no-object chip known to man.

Run the Core i7 975 Extreme Edition through any imaginable battery of benchmarks and it will return superior results to every other CPU currently available every time. The slight snag is the 975's punitive pricing: it will lighten your wallet to the tune of nearly £800.

To that figure, you then have to add hundreds more for a motherboard, a hefty helping of system memory, a decent graphics card and various items of PC paraphernalia. It all mounts up very quickly. Back in the real world, therefore, money does matter.

In turn, that makes CPU selection rather more complicated. Even if you do stick with Intel, for example, there are currently no fewer than three distinct sockets to choose from, each supporting a small army of processor models. Plus with value for money in mind you'd be unwise to disregard AMD.

It may not be able to compete with Intel on raw computational horsepower at the moment, but AMD has pulled out the stops on pricing. It has some incredible bang for buck on offer. Of course, the age-old AMD or Intel question is just one of many conundrums facing the intrepid CPU buyer.

Increasingly one must choose between maximising operating frequencies or core counts. If you're on a budget, so the conventional wisdom goes, you can't have both. That certainly seems to be the case if you make a comparison of processor models based on advertised clockspeeds.

Throw overclocking into the mix, however, and the pecking order changes rapidly. There are some real giant-killer CPUs out there if you're willing to have a go yourself.

Back to the future

Next, there's the question of future-proofing. One of the PC's greatest strengths has always been its ability to reinvent itself through constant technological progress and innovation. Nevertheless, some CPUs and their associated sockets and platforms are longer for this world than others.

AMD has a better track record than Intel for maintaining both backward and forward compatibility when it comes to this area. This is the kind of detail that might just swing your decision when much else is equal. If we're talking platform comparisons, there are a number of further factors to consider.

At first glance, two processors might seem closely matched in terms of price and performance. But add the supporting platform to the equation and a yawning gap can appear. Motherboards compatible with Intel's latest CPUs, for example, are still quite pricey.

Likewise, a cheap Core i7 chip is a false economy if you can't afford enough triple-channel memory to do it justice. As ever, it's horses for courses. For that reason, we've reduced the bubbling mass of CPU models available to just four hard-boiled devices. Each represents a respective best in class in the categories of value, future-proofing and overclocking, with the fourth and final our all-round top chip.

Clocks vs cores

Let's put the thought of prizes to one side for now and attack the first major conundrum, that of clocks and cores. If you can't have the best of both, which should take preference?

On the one hand, not all application types are keeping pace with the reality of multi-core hardware. Web browsing and gaming are the two most obvious examples of software types that have remained at least somewhat resistant to multi-threading efforts. Until the challenge of coding such multi-threaded software is overcome, multi-core processors will not fulfil their potential.

On the other hand, there's no doubting that the PC industry as a whole has effectively bet the farm on threaded software and multicore processor architectures. Wind back the clock to around 2004 and it was becoming increasingly apparent that the clockspeed-centric approach to ever-greater performance had hit a wall, on top of which was a large neon sign flashing '4GHz'.

But if the quest for ever-higher clockspeeds had come unstuck, advancements in integrated circuit production technology were allowing engineers to squeeze ever larger numbers of transistors into computer silicon chips. The only way to make the most of these increasing transistor budgets and therefore keep performance moving forward was to add more cores.

Thus we had what Intel now calls its 'right-hand turn'; the industry changed tack in favour of the current multi-core architectures.

The reign of multi-core

Most computationally demanding applications, including image rendering and media encoding, are already highly threaded and multi-core friendly. That will only become truer in future. Indeed, the more cores your CPU packs, the more you will find its performance potential is increasingly unlocked over the next few years as software developers hone their threading prowess.

Gaming is a good example here. Thanks to the recent release of Windows 7 and improved support in the new DirectX 11 API, games should be able to exploit multi-core chips much more effectively. What's more, the more cores you have, the better your PC will be for multi-tasking. These days, who doesn't have a plethora of apps running simultaneously?

As a general rule, then, we reckon the more cores and threads your processor can pony up the better. Consequently, quad-core is what you should be aiming for. That's especially true given that four cores can now be had for well under £100.

Admittedly, AMD has confused the issue somewhat with its triple-core X3 processors. Indeed, in some instances, a triple-core processor with a healthy helping of cache memory will outperform a similarly priced quad-core processor with cut-down cache. But such scenarios will become rarer and rarer going forward.

The final and clinching argument is that while overclocking can be used to increase operating frequency, adding cores to your CPU tends to be much more difficult – if not always impossible.

Intel vs AMD

Now that we've established quad-core as the basic configuration of choice, should it be four Intel cores or four from AMD?

Well, Intel will currently sell you quad-core chips under the Core 2, Core i5 and Core i7 brands while AMD will supply you with both Phenom II and Athlon II CPUs in quad-core trim.

The easiest processor to discard is Intel's elderly Core 2. That's not because it's a weak performer or represents poor value – it's still a nice chip.

No, the problem is the aging LGA 775 socket that comes with it. It's a dead end and is soon to be killed off. If you already have an LGA 775 system and seek only to upgrade your CPU, the Core 2 is fine. But LGA 775 is a no-no for new PC builds. It has no future.

On the broader AMD vs Intel question, a large part of the answer comes down to cost. The more constrained your budget, the more AMD's processors make sense. The key point here is to look beyond the headline price of a given processor.

DECISIONS, DECISIONS: The decision of Intel over AMD is not as straightforward as you might think

You might, for instance, compare AMD's Phenom II X4 965 Black Edition chip to Intel's new Core i5 750, two processors that compete in the sub-£150 market. For the most part, this pairing delivers very similar performance, save for gaming where Intel has a clear edge. Add to that the fact that the Core i5 can occasionally be had for a few quid less and you might think that it's the obvious choice.

However, factor in motherboard prices and the winner is much less clear. Currently, only Intel's P55 chipset is compatible with the LGA 1156 socket required for Core i5 processors. You'll struggle to find a P55 motherboard for less than £80. By contrast, £45 is enough to secure a motherboard fit for the Phenom II.

Making matters worse for the Intel chip is the fact that it requires pricey DDR3 memory. For the AMD CPU you can opt for either DDR3 or cheaper DDR2 memory through your choice of the AM3 or AM2+ sockets respectively, both of which are compatible with Phenom II and Athlon II processors. This allows you to further cut costs, though you should remember that choosing the older AM2+ socket could limit your options for CPU upgrades in the future.

It wouldn't surprise us if AMD's upcoming six-core processor was only compatible with AM3 motherboards.

Intel makes things even tougher when it comes to choosing between sockets. With its new Core i5 and Core i7 family of processors it has introduced two incompatible sockets, LGA 1156 and LGA 1366. On paper, they form the basis of mainstream and high-end platforms respectively.

Unfortunately, Intel in its wisdom has chosen not to align its processor branding with the realities of the underlying hardware. So, while the Core i5 chip is indeed reserved for the LGA 1156 socket, Intel sells Core i7 chips in both formats, denoted in Intel's new product nomenclature as the Core i7 800 and 900 series respectively.

Significantly, these two flavours of Core i7 are distinctly different in terms of underlying architecture. Firstly, the 900 series chips and therefore all LGA 1366 boards sport a triple-channel memory interface. In other words, you have to have three rather than two sticks of DDR3 memory in order to achieve the maximum bandwidth.

Secondly, all chips on the LGA 1156 platform (that's all Core i5 processors and the Core i7 800 series CPUs) have 16-lane PCI Express controllers integrated into the processor die. Compared to the LGA 1366 platform – and indeed many AMD-based platforms, which often provide 32 or more lanes – this places a cap on the number of high-performance PCI Express peripherals, such as graphics cards, that can be attached.

For your average PC user that's hardly a crushing limitation, but it's worth bearing in mind should you wish to run multiple video cards or perhaps use a GPU as a general-purpose coprocessor in the future. Such high-end configurations will not necessarily be impossible, of course but there will certainly be some limitations that don't apply to those platforms that feature 32 or more PCI Express lanes.

The final issue concerns futureproofing and upgrade paths. LGA 1366 will be Intel's high-end socket for the foreseeable future. Early next year Intel will unleash its new six-core monster, codenamed Gulftown. It will only be available in LGA 1366 trim. Hence, with Intel platforms you can no longer buy a cheapish motherboard and drop in a high-end CPU later. You need to invest in the full platform.

Right now, however, there's actually remarkably little difference in terms of performance between the various Core i7 processors operating on the LGA 1156 and LGA 1366 sockets. In fact, thanks to an aggressive implementation of Intel's automatic overclocking feature (which is known as Turbo Boost), LGA 1156 can sometimes be faster.

In other words, unless you plan to upgrade to a six-core processor chip next year, there is probably little sense in paying extra for the pricier LGA 1366 processors and motherboards at the moment. Your current needs will be easily fulfilled by a processor on a cheaper LGA 1156 socket.

Prioritising features

Finally on Intel processors, it's worth noting that the lack of HyperThreading on the Core i5 700 series compromises performance in highly threaded apps by as much as 25 per cent.

HyperThreading is Intel's symmetric multi-threading technology. It allows a single core to crunch two software threads at the same time. Hence, quad-core Core i7 processors make eight logical processors available to a PC's OS.

HYPERTHREADING: The Core i7 has up to 8 cores available, four of which are virtual cores

As for AMD's Phenom II and Athlon II chips, there are fewer foibles to grapple with. Your choice essentially boils down to cores, clocks and cache memory. Both processor families are available in dual, triple, and quad-core configurations running at a wide range of clockspeeds.

Regarding cache memory, the key difference is level three (L3) cache: Phenom IIs have it, Athlon IIs don't. The lack of L3 cache hurts the Athlon II's performance compared to otherwise similar Phenom II chips to the tune of 10 to 15 per cent. It's significant, but certainly not a deal breaker.

That's because the underlying architectures of AMD's two key processor families are essentially the same. Combined with AMD's far more flexible platforms in terms of socket compatibility, it makes for a much more straightforward range of CPUs than Intel's increasingly baffling chips.

Overclocking issues

All of which leaves us with one final issue to address: overclocking. In the past, trying to squeeze extra performance out of a PC processor was not only dangerous but also often futile. For starters, processors and motherboards tended to lack fail-safe circuitry that protected them from the effects of running at increased frequencies and voltages. Torching your pricey processor was a genuine risk.

At the same time, the amount of headroom on offer was often rather modest. Five or six years ago, a 10 per cent overclock was a decent result. Today, all that has changed. Not only is overclocking much safer than before, the results can be truly spectacular. It's not unusual for Intel processors to overclock by as much as 1.5GHz. That kind of boost can translate into a huge performance increase of 50 per cent or more.

Intriguingly, however, it tends to be processors in the middle to lower order of any given processor family that offer the best results. Put simply, processor architectures usually have a frequency ceiling beyond which they won't operate. This applies almost regardless of their official operating speed.

For Intel's Core i7 chips, that limit is often around or just above the 4GHz mark. Take the Core i7 920 processor, for example. Officially it's a 2.66GHz chip and yours for around £200 – but when overclocked (using standard voltages), it's usually capable of stable frequencies of around 4GHz to 4.1GHz.

However, the 3.33GHz, £750 Core i7 975 only increases that headroom to 4.3GHz or so. That's over three times the price for a speed advantage of just five per cent.

Broadly speaking, AMD's chips tend to be a little less overclockable and top out at approximately 3.7GHz to 3.8GHz. However, the same philosophy applies. The higher up the chip range you go, the less headroom you get.

The lesson here is that if you are willing to dabble in a little overclocking, you can enjoy the very best processor performance either AMD or Intel can currently offer, but at a mere fraction of the price. That's got to be worth a try.

Snapdragon mobile device chips have a competitive advantage because of their integrated 3G and wireless capabilities, believes Qualcomm.

In a technology briefing with TechRadar, the company added it would be announcing a 1.5GHz dual-core version of the Snapdragon chip later this year.

Luis Pineda, Senior Vice President of Product Management at Qualcomm CDMA Technologies, said that new Snapdragon chips are imminent.

"The next Snapdragon is our 45nm version, starting this month [currently the 65 and 80nm parts are in circulation]. We'll have the 45nm 8X50A at 1.3GHz and then the dual-core which will be available in the second half of this year, in products for 2011, at 1.5GHz, the 8X72." The latter chip will have full 1080p capabilities.

Pineda also welcomes Intel's low-power processors and Nvidia's Tegra 2, though is clear to state what he perceives Snapdragon's competitive advantage. "We see this as an absolute confirmation of how important this market is to the industry and to consumers. They are very capable competitors, leaders in their areas and it brings a bigger challenge for us as we enter this space beyond the cellphone."

• Nvidia's Tegra demo wows CES

"It pushes us harder to deliver industry-leading chips. The key differentiators and advantages we believe we have is our long history of wireless expertise and an integrated approach. Nvidia is an application processor – no integrated wireless, 3G. Intel is the same.

"So that's a key value we bring to the consumer – that's what's enabling phones to be as thin as possible. It's not surprising that Intel and Nvidia are prioritising this area more."

Pineda then moved onto Snapdragon-based netbooks, a category Qualcomm refers to as smartbooks*. We asked that, given the previous lack of success of Linux on netbooks, can non-Windows netbooks be successful? "I could talk forever about that, but in short we're not looking to build a laptop. We're not looking to enable a netbook – those are Windows-based devices.

SNAPDRAGON NETBOOKS: HP showed off its Snapdragon-based netbook at CES

"Consumers think that netbooks are just a cheaper PC. We're developing a new category – a smartbook, to deliver a new connected experience for social networking, web-based apps, browser, email, push-based services similar to your smartphone.

"Our strategy is to focus on user experience - which OS is not as relevant." Pineda added that Qualcomm was one of Google's partners for the upcoming Chrome OS.

• Hands on: Lenovo Skylight review

Pineda was also keen to stress the strength of Qualcomm's strategy as an ARM partner. "We're one of a handful of architectural licensees where we have the licence to modify and still comply with the instruction set, but build our own custom microprocessors.

"We've done that on the Snapdragon... it's based on the V7 instruction set, but it's not one of their standard Cortex off-the-shelf cores. We did our own custom CPU... [we] optimise the trade-off between performance and power so we have full rights to that and it's our own custom CPU.

"We own the core, we designed the core, but we license the instruction set. The strategy of Qualcomm is paying off because we differentiate our CPU versus Texas Instruments, Marvell, Freescale. We've built up a large team which gives us the skillset and technology capability to build future instruction sets."

*Smartbook is a registered trademark of Smartbook AG, but in this interview Pineda uses smartbook as a generic term for a device which falls between smartphone and netbook.