The new processors carry performance ratings that are already well known - 4000+, 4400+, 4800+ and 5000+ - but the cache and clock speed configurations are different from what we've seen before. The 4000+ to 4800+ versions have half the L2 cache of the 90 nm Windsor chips (2x 512 MB instead of 2x 1 MB), but they run 100 MHz faster to make up for the negative impact on performance of the smaller size. We've listed all the old and new Athlon 64 X2 models on one of the following pages, to give you the full overview.

AMD was considerate enough to place the new 65 nm Brisbane core into the existing Socket AM2 processor package (940-pin socket), making the new models fully compatible with existing motherboards. You will have to update the BIOS to a new version that supports the 65 nm Brisbane processors, however, before installing a Brisbane chip and starting the system. Check out the website of your motherboard vendor to find a current BIOS image file. You will also need a BIOS update program, which most companies now offer as a Windows tool.

The new processor behaves very much like the 90 nm ones. Windows recognizes it as an Athlon 64 X2, and automatically enables Cool'n'Quiet if the feature is enabled in your BIOS and the Windows energy profile is switched to laptop/mobile. AMD states that there should be no performance difference between 90 nm and 65 nm Athlon 64 X2 processors, which is not entirely true. The new models come with longer L2 cache latencies of 20 clock cycles, instead of Windsor's 12 cycles at popular 128 MB chunk sizes, which introduces a minor disadvantage. We found application performance to be exactly on the level of the 90 nm processors, so we focused our benchmarking on the L2 cache differences.

The 65 nm Brisbane core carries the F1 stepping, but its technical data does not vary much from that of older cores. Even the core voltage hasn't changed much.

The 65 nm Brisbane is still a Socket AM2 processor with 940 pins, and can be used in all Socket AM2 motherboards after updating the BIOS.