Intel Core i7-3960X review

We tested the Intel Core i7-3960X on an Asus P9X79 Pro motherboard. In our benchmarks, the processor managed an overall score of 123, helped by a strong score of 128 in the image editing test and 133 in the multitasking test. Like Sandy Bridge processors, Sandy Bridge E chips can Turbo Boost to run higher than their stock speeds in lightly-threaded applications; the i7-3960X increased its speed from 3.3GHz to 3.9GHz when running the single-threaded image editing benchmark.

The processor’s six cores also helped in the multitasking test, where the image editing and video encoding benchmarks run at the same time as playing a high-definition video. To check the performance of the individual cores, we disabled all but one core then ran our benchmarks again. With only one core active the processor managed 29 overall – exactly the same as when we ran the benchmarks on one core on an Intel Core i5-2500K, showing the Sandy Bridge E to be essentially a Core i5-2500K with two extra cores.

Strong performance in multitasking, but slower than we were expecting in video encoding

We were surprised, however, that the processor only managed 105 in the video encoding test, which is not much better than a £170 quad-core Intel Core i5-2500K, which scores 100. Video encoding has traditionally taken advantage of multiple cores, and the i7-3960X’s six cores should give it an advantage. However, as we found in our AMD FX-8150 Bulldozer review, many applications struggle to take advantage of more than four cores. During the video-encoding test, Windows Task Manager showed that the i7-3960X didn’t go above 40% usage. Even in the multitasking benchmark we only saw 40-50% usage.

When running two sets of the benchmarks at once, the Core i7-3960X begins to shine

To really max out the processor, we ran two sets of our benchmarks at once, then calculated the average of the scores. In this double benchmark, the processor finally hit 100% usage in the multitasking test, and managed a score of 95 overall – far better than the 56 a Core i5-2500K processor managed in the same test and around 30% faster than the AMD FX-8150 chip’s 64. If you need to run multiple intensive tasks side by side, this is the fastest chip we’ve seen yet.

Next page: overclocking and conclusion