AMD Athlon II X4 620 review

AMD has released so many processors recently that even we've been struggling to keep up. It has even muddied the dividing line between its brands, launching the first dual-core Phenom chips, and now the first quad-core Athlon.

Making a quad-core processor that sells for just £73 is impressive. The next cheapest AMD quad-core we could find, a Phenom X4 9950 Black Edition, cost around £100. Intel's cheapest quad-core processor, the Core 2 Quad Q8200, costs around the same. With a clock speed of 2.6GHz, the X4 620 is no slouch, but corners have inevitably been cut.

It has no more memory cache than its dual-core Athlon II counterparts. There's the usual 128KB of L1 cache, but only 2MB of L2 cache. The dual-core models have 1MB per core, but here it's split four ways for just 512KB per core. This is the same as the high-end Phenom II's, but the X4 620 lacks the Phenom's 6MB shared L3 cache to distribute incoming data efficiently.

This architectural limitation was visible in our benchmarks, as the X4 620 struggled in our multitasking benchmark. Compared with the equivalently clocked Phenom II X4 810, the X4 620 was a huge 17 points slower. This is because a small cache makes it hard for the processor to deal efficiently with multiple intensive tasks. On the plus side, it matched the X4 810 in our video encoding test, despite costing around £50 less.

It was also slower than most in games, where the small cache caused problems we only usually see on Intel's cheapest Pentium and Celeron dual-core chips. It dropped around 7fps in Call of Duty 4, so it's not ideal for games.

If your budget is tight and you want a quad-core processor specifically for video encoding, the X4 620 is a bargain. However, this is rather a niche requirement. Most users will be better served by a dual- or triple-core processor with a larger memory cache and higher clock speed. We recommend the Phenom II X2 550 Black Edition, which costs only £71 from www.pixmania.co.uk.