AMD FX-8350 review

The FX-8350 is the first of AMD’s 2012 range of performance processors. There’s a clock speed boost and a new core design, which AMD hopes will start to close the performance gap between its chips and Intel’s all-conquering Core range.

The new processors aren’t that much different to the older versions. The top-of-the-range FX-8350 and FX-8320 have eight cores, while down the range you have a six-core FX-6300 and four-core FX-4300. They still use the AM3+ socket and need the AMD 970, 990X and 990FX chipsets.

AMD sent us the high-end FX-8350 processor to test. This has a huge eight cores, arranged in four modules of four cores each. Each module shares a 2MB block of level 2 cache, while all four modules share an 8MB pool of level 3 cache. This modular approach is meant to share cache more efficiently, as each of the two cores in each module can access more level 2 cache when necessary than if the cache was split evenly across all eight cores.

The cores themselves are updated, from last year’s “Bulldozer” to this year’s “Piledriver”. The new core has the same 32nm process but a host of microarchitecture improvements, and the maximum clock speed for the high-end chip has jumped from 3.6GHz to 4GHz. The maximum speed the processor can reach in Boost mode, where the chip can dynamically overclock where there’s enough thermal headroom, hasn’t changed, at 4.2GHz.

Four sets of two Piledriver cores in AMD’s new performance chip

In our tests of last year’s Bulldozer-equipped AMD FX-8150, our main criticisms revolved around the fact that few, if any, Windows programs are optimised to take advantage of so many cores. We found that even video-encoding, which traditionally works well with multiple cores, could only use around 50% of the processor. This put the FX-8150 at a disadvantage over Intel’s processors, as each individual core was slower and the advantage of having more than four cores was all but nullified by software limitations.

Unfortunately, this is still the case with the new processor. The new chip is significantly faster than the old one, but most applications still don’t use it to its full potential. During our multi-threaded video encoding benchmark, for example, processor usage never got above 54%. Even during the multitasking test, which runs all our benchmarks together while playing back a high-definition video, processor usage never got above 70%. In comparison, Intel’s quad-core Core i5-3570K ran at 100% usage in both video-encoding and multitasking tests, leading to superior scores.

AMD’s new chip is as quick as last year’s Intel equivalent, but this year’s rival has pulled ahead (CLICK TO ENLARGE)

The FX-8350 managed a score of 102 overall in our benchmarks, which is a 17% improvement over last year’s FX-8150. This also puts it on an equal footing with the Intel Core i5-2500K, which was our favourite processor from last year. However, this year’s equivalent, the Core i5-3570K, has pulled ahead with an overall score of 121.

The Intel processor also had superior core-for-core performance, as demonstrated when we disabled all but one core on both processors and ran our benchmarks again. In this core versus core comparison, the Core i5-3570K came out with 39 overall, compared to 27 for AMD’s processor.

It may have eight of them, but AMD’s cores aren’t as quick as Intel’s (CLICK TO ENLARGE)

The FX-8350 may be slightly cheaper than the Core i5-3570, but judging by US pricing (UK prices have yet to be confirmed) there’s only about 15% in it, so AMD’s chip can’t quite match Intel’s pound for pound.

As with last year’s Bulldozer chip, we could only take full advantage of the FX-8350’s eight cores by running two sets of our benchmarks side by side, so the PC was encoding two videos while playing back two high-definition videos at the same time. This put the processor up to 100% usage and led to an impressive overall score of 80, while Intel’s chip, with its four-core deficit, could only manage 59 overall. This is a pretty unlikely usage scenario, however.

When you’re doing some truly silly multitasking, the FX-8350 definitely has an advantage (CLICK TO ENLARGE)

The processor’s overclocked multiplier makes it simple to overclock. Using the stock AMD AM3+ cooler, we pushed the clock speed up to 4.4GHz, but this 10% overclock only led to a 5% improvement in our benchmarks, to a score of 107.

AMD’s new FX-8350 is a definite improvement on last year’s model, and is now easily quick enough for all desktop tasks. However, as with last year’s FX-8150, there are very few programs that can take advantage of eight cores, and the processor’s core-for-core performance still lags behind that of the Intel competition. If you want to run as many programs as possible at once this is still the multitasking king, but most new system builders would still be better off with Intel’s Ivy Bridge processors.