AMD has launched a significant new platform called AM2. While it's clear that it won't have the performance impact Intel's Core Duo did four month's ago, this will still undoubtedly shake up the industry.

On a basic level, AMD's desktop processors move from 939 pin to 940 -- but not quite in the same configuration as existing Socket 940 Opteron systems. AMD's Virtualisation technology (known as 'Pacifica') is now supported and, most importantly, DDR2 memory will now be supported. The fabrication process remains at 90nm.

Appearances
The launch brings some practical considerations, and yes, existing socket 939 users will find their upgrade path effectively at an end. Upgraders should also note that the new heat sink fan (HSF) cage connector sports just one connection bar to 939's three. Consequently, most reference coolers will still fit, but more exotic coolers may not.

Memory
The change isn't simply about AMD being awkward and forcing incremental upgraders to replace the guts of their entire system. Rather, one of the most widely-reported motivations for AMD is to finally secure compatibility with DDR2 memory, which is now cheaper to produce than straight DDR. The new memory controller is what necessitated the new socket type and the 800MHz speed of PC2-6400 RAM will be supported.

It's worth noting that Intel has been planning a move to PC2-6400 memory for some time so it makes sense for AMD's desktop processors to tag along. This, in part, is thought to explain the timing of AMD's announcement, though AMD will also want a long lead time before the launch of Intel's, next-generation processors later this year.

Performance
Performance of Intel systems didn't accelerate particularly when it moved to DDR2 as the higher clock speed was countered by the higher latencies. However, it is interesting to see how AMD's architecture copes. We got our hands on a 5000+ and tested with MSI's K9N SLI Platinum motherboard and our standard test bed components generated a score of 1.28 - about the same speed as an FX-60. Previously, a socket 939 4800+ was three percent slower with 1.25.

However, this used PC2-4200 (533MHz RAM) rather than PC2-6400 which was unavailable. We also ran the same benchmarks using 2GB of high performance PC2-5300 (667MHz) RAM and achieved a score of 1.30 - just two percent faster. It's unlikely that PC2-6400 will improve on this. We were unable to obtain an AM2 4800+ for an 'apples to apples' comparison so claims that AM2 is faster are based on nothing more than the fact that newer and faster chips generally are.

New chips
Most of AMD's existing 939 processors look to be relaunched with the AM2 architecture from single core Sempron 3000+ and upwards. At the high end though, an X2 5000+ processor (running at 2.6GHz) leapfrogs the 4800+ while the new fastest model will be the FX-62 (running at 2.8GHz).

Expected Lineup of AMD's new AM2 Desktop processors
Dual Core Processors Speed
Athlon 64 FX-62 2.8GHz
Athlon 64 X2 5000+ 2.6GHz
Athlon 64 X2 4800+ 2.4GHz
Athlon 64 X2 4600+ 2.4GHz
Athlon 64 X2 4400+ 2.2GHz
Athlon 64 X2 4200+ 2.2GHz
Athlon 64 4000+ TBC
Athlon 64 3800+ 2GHz

Single Core Processors Speed
Sempron 3800+ 2.4GHz
Sempron 3600+ TBC
Sempron 3500+ 2.2GHz
Sempron 3400+ TBC
Sempron 3200+ TBC
Sempron 3000+ TBC

Really, really small
It's interesting to note that Intel's next generation chip, previously code-named Conroe and Merom but now known as Core 2, will be fabricated using the 65nm process while this first generation of AM2 chips remains at 90nm. AMD is not planning to move to 65nm until the end of the year. While early reports suggest Core 2 can wipe the floor with an FX-60, who knows where AMD will be, or what the company will be about to launch by the time it appears.