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Processors

Posted on 12 May 2008 at 10:54

The first step to building your PC should be to decide on a processor, as this will take centre stage in your new system. Although overall PC performance is affected by many different components, the CPU is the most influential. But it can also be one of the most expensive parts of the system. Prices range from £20 to £800, with great variation in architecture, clock speed and number of cores.

Unless you're building a low-power PC, your decision rests between two manufacturers - AMD and Intel. At the moment, Intel's Core 2 processors have the upper hand in terms of performance, but AMD has great-value options where raw speed is less of an issue. For most mainstream PCs, though, the Core 2 or Athlon X2 ranges provide the most processing power for your money.

Beyond this, it's a matter of what kind of applications you'll be running. Although quad-core processors sound like the fastest option, in reality this depends on whether your software can actually take advantage of multiple processing cores. Most apps still can't, which makes dual-core more cost-effective. Even though AMD's quad-core Phenom 9500 can be had for scarcely more than £100 (exc VAT), for a budget system we'd still recommend a similarly priced dual-core CPU for everyday uses.

If you're on a severe budget, a single-core processor can be had for as little as £15, such as AMD's Sempron LE-1100, running at 1.9GHz. Unless every penny counts, though, we recommend going for at least a dual-core model - the extra responsiveness will ease your everyday computing, even if the performance with individual applications won't be improved that much. AMD's Athlon X2 4800+, running at 2.5GHz, is superb value at £42. So this is what we selected for our budget PC. We chose a retail version, which comes with a heatsink and fan unit, for even better value. The cooler supplied won't be as quiet or as strong in performance as those you can buy separately, but it will save you around £10.

For gaming and performance enthusiasts, the most extreme platform on the planet is Intel's SkullTrail, which borrows a fair number of components from the company's workstation and server division to make a monster dual quad-core PC with both SLI and CrossFire multi-graphics options. But you'll need to remortgage your house and sell one or two vital organs to afford it, as the required Intel Core 2 Extreme Q9775 processors cost a grand each (you need two), with the motherboard nearly £400.

For an affordable high-end gaming rig, a more pedestrian quad-core processor will suffice. Even games aren't taking much advantage of multiple cores just yet, although Crysis does benefit. Intel's Core 2 Quad Q6600 has developed a near-legendary status; not only is it Intel's cheapest quad-core, but it also has huge potential for running at a much faster clock speed than originally specified. This is particularly true of the G0 stepping, which is usually the only Q6600 available these days.

The Q6600 is good, but Intel's latest 45nm quad-core processors are even better. We've opted for the mid-range Core 2 Quad Q9450 running at 2.66GHz in our gaming PC. Even if four processing cores aren't that beneficial now, they will be before the end of the PC's life. A Core 2 Duo E8200 running at the same speed costs around £85 less, and would make a good compromise. But with the Q9450 available for £186, going quad isn't going to ruin our £1,200 budget. Intel's 45nm processors are also less power-hungry than their 65nm predecessors. If you fancy getting more from your investment by raising the clock speed, the 45nm quad-core processors have plenty to offer.