AMD FX-8150 review

PERFORMANCE TESTING

We paired the processor with 4GB RAM and ran our benchmarks, which consist of intensive image conversion, video-encoding and multitasking tests. In these tests the Core i5-2500K manages 100 in each benchmark. The FX-8150, however, could only manage an overall score of 85 – see below for the full results.

The problem seemed to be that our benchmark software was struggling to take advantage of all the cores. Even when video-encoding, where multi-core processors are normally strong, Windows’ Task Manager only showed the FX-8150 at 45-50% processor load. In contrast, during the same test the Core i5-2500K stayed at between 90% and 100% usage. Windows’ processor usage graph (below) shows that one FX-8150 core was under heavier use than all the others, showing that the program’s threads aren’t evenly balanced across all the cores, which caused a bottleneck.

When video-encoding, the first core is under heavy load, but the rest hover below the 50% mark

To double-check we installed Sony Vegas Movie Studio HD Platinum 11, and encoded a 1080p AVCHD video to 1080p Blu-ray format at 24fps. On the Intel Core i5-2500K we saw processor usage of 80-85% and the video encoded in 12m 43s, but on the FX-8150 the processor sat at between 65 and 75% usage and it took 14m 11s to encode the video.

This shows that even multithreaded applications such as video encoding can’t take advantage of the FX-8150’s eight cores efficiently, and as an individual Bulldozer core seems slower than the equivalent Intel Core i5-2500K core, despite the Bulldozer’s 300MHz faster clock speed, this holds it back in application performance. To compare core-to-core performance, we disabled all but one of the cores on both our Intel Core i5-2500K and AMD FX-8150 test systems and ran our benchmarks again. The Core i5-2500K managed 29 overall and the Bulldozer managed 25, showing each of AMD’s cores to be 14% slower than its rival from Intel. We also underclocked the FX-8150 to 3.3GHz (the same clock speed as the Core i5-2500K) and re-ran the test. With one core and the same clock speed, the FX-8150 scored 24, compared to the Core i5-2500K’s 29.

AMD single-core

Intel single-core

AMD’s latest can’t match Intel’s rival in a core-for-core comparison

To try to run all the FX-8150’s cores at maximum usage, we ran two sets of our benchmarks at once. Here, both the FX-8150 and the Core i5-2500K ran at 100% processor usage at all times. Once we’d calculated the average of the two benchmark scores, we saw that AMD’s chip had finally managed to pull ahead, with an overall score of 82 compared to the Intel processor’s 63. This shows that the FX-8150 can have an advantage, but only if you run incredibly intensive tasks such as encoding two HD videos at once to another format or encoding two HD videos while playing back a third.

AMD multi-benchmark

Intel multi-benchmark

Under incredibly intensive multitasking, the FX-8150 has the edge over Intel’s Core i5-2500K

Next page – overclocking and conclusion