Intel Core i7-2600K review

With Turbo Boost, we initially thought Intel was trying to bring overclocking out of its murky hobbyist niche. However, with Sandy Bridge it’s gone well beyond that, with affordable and easy to overclock processors. Previously, the only Intel processors with an unlocked multiplier were incredibly expensive Extreme Edition chips. Now, both Core i7 and Core i5 ranges have a K-designated processor with a fully unlocked multiplier. These cost a few pounds more than the regular versions, which you could view as a rip off, as Intel are charging you simply to disable their own security. Then again a lot a of time and research has gone into making these chips run fast and cool, and it’s overclocking enthusiasts who will benefit the most from that effort.

The new processors have a low base clock speed of just 100MHz. This means you can make fairly fine speed adjustments by adjusting the multiplier setting. Overclocking primarily via the multiplier is an essential change, as pushing up the base clock speed throws out other devices and data buses associated with the processor. To overclock the processor, you simply raise the maximum multiplier ratio in the BIOS. Even the locked versions of the chips can have their multipliers raised by up to four steps, equivalent to 400MHz, while the K-designated chips are theoretically unlimited.

We pushed up the multiplier by four steps on our Core i7 chip, to a maximum clock speed of 4.2GHz. We had no stability problems and saw the overall score shoot up, as it ploughed through our benchmarks at high speed. Once overclocked in this way, we noted that Turbo Boost became far more aggressive than normal, maintaining the top speed almost constantly. This produced an incredible overall score of 214, and this from just a minor overclock available on even the locked version of the processor.

These overclocks raise the maximum target speed, so the processor will throttle back if it overheats. However, by using a large tower heat sink with three heatpipes, we saw the chip maintain 4.2GHz throughout even our multi-threaded video encoding test. Don’t expect to see this consistent performance using the smaller stock heat sink.

Better still, Intel’s SpeedStep still functions when the processor is overlocked, so it drops back down to a x16 multiplier when it’s idling – keeping things quiet, cool and power-friendly. The processors are incredibly power efficient anyway, with a TDP of just 95W, and that covers CPU and graphics, remember.

Much of the thinking behind the new architecture has been informed by designing a mobile processor. That includes the built-in graphics, clever power management and a small physical package. However, none of these are unwelcome in a desktop PC either, and with benchmark results like these, it’s impossible to complain about the result.

The Core i7-2600K is an incredible processor, and a worthy winner of our Ultimate award. However, unless money is no object, you shouldn’t buy one. That’s because the Core i5-2500K is available for around £80 less, that’s almost the price of a compatible motherboard, and yet retains the vast majority of this chips performance.