Intel Core i5-661 review

Intel has released its latest range of processors, codenamed Clarkdale. The new range of 32nm chips consists of both Core i3 and Core i5 branded models, all with built-in graphics processors. This Core i5-661 has the second fastest clock speed of all the new chips, but is far better value than the top-rated i5-670.

The i5-661 is a dual-core processor, but the addition of Intel's Hyper-Threading technology makes Windows see it as having four processing cores. Though Hyper-Threading does give a noticeable boost in multi-tasking, it can't compete with a true quad-core processor, such as the Core i5-750.

The built-in memory controller gives super-fast access to the motherboard's memory slots. You have to use DDR3, although prices have now dropped far enough to not make this a problem. You can get 4GB of 1333MHz DDR3 for around £80 including VAT; by comparison 4GB of DDR2 only costs around £5 less.

The i5-661's base clock speed is an impressive 3.33GHz. As with the Core i5-750, Intel's Turbo Boost technology automatically overclocks the processor during tough tasks, to a maximum speed of 3.6GHz. To keep the processor from overheating the full boost is only ever applied to one core at a time. The i5-661's maximum boost of 266MHz is small compared to the i5-750's 533MHz, but that processor's maximum Turbo Boost speed is only 3.2GHz.

The i5-661 is certainly no slouch then, but its higher clock speeds are tempered by a smaller 4MB L3 cache, with the i5-750 having 8MB. Its performance is largely similar to the i5-750's, except in our Multi-taking test where the older processor's bigger cache and four processing cores were clearly superior.

We tested it using the Asus P7H57D-V EVO, a motherboard that uses the H57 chipset. Boards with H55 and Q57 chipsets are also compatible. All these boards will have the necessary HDMI, DVI or VGA outputs to let you make use of the processor's integrated graphics chip.

The i5-661's graphics chip is the fastest in the range, running at 900MHz. It could only produce 10fps in our Call of Duty 4 test, making it unsuitable for modern 3D gaming. The faster graphics chip pushes up the TDP of this processor to 87W, compared to 73W for the rest of the range. In most respects it's largely similar to Intel's GMA X4500 HD chip. Improvements include hardware acceleration for dual video decoding, post-processing for HD video sharpness and dual HDMI output.

The Core i5-661 is revolutionary in a number of ways, such as its integrated graphics chip and 32nm manufacturing process. It's a good choice if you’re looking to build a powerful PC with integrated graphics and good onboard audio capabilities. However, the similarly priced i5-750 is still a better buy for the majority of demanding PC users, thanks to its four processing cores and big 8MB memory cache.