Labs

The dual-core Athlon 64 X2 range comes in versions for Socket 939 and newer Socket AM2 motherboards. The 939 version has the same amount of cache, but supports only DDR and not DDR2 RAM. We tested the 2.2GHz and 2.4GHz versions.

Our Socket 939 motherboard's slower DDR memory made little difference in our benchmarks. Both the X2 4200+ and X2 4600+ were two points slower than their Socket AM2 equivalents in the video-encoding test, while the Socket 939 dual-core processors were slighter faster than the AM2 variants in the image-editing test.

The X2 4200+ and X2 4600+'s overall Shopper benchmark scores of 152 and 163 put them in the middle of the group. Overclocking the processors was unsuccessful due to heat problems.

These chips are slightly slower than Intel's similarly priced Core 2 Duo E6300 and E6400, but the performance difference isn't big. Combined with a cheap Socket 939 motherboard, they make cost-effective upgrades, especially if you can reuse your old DDR RAM. This is especially true of the Athlon 64 X2 4600+, which is almost as fast as an Athlon 64 FX-60, and £370 cheaper.