In terms of processor pin count, the new socket was not really necessary to support DDR2 memory. However, AMD decided to make physical modifications in order to prevent people installing the wrong processor into their systems. So Socket AM2 (or M2, as it was called before hitting intellectual property issues) has a total of 940 pins. Despite this, it is also not pin-compatible with the Opteron's Socket 940.
Simultaneous to the AM2 platform launch, AMD will also release a full processor line that consists of six Athlon 64 X2 dual cores, two Athlon 64 single cores, and six Sempron class value processors. In addition to these, AMD will respond to Intel's announcement that it will fit all mainstream desktop processors into a 65 W power envelope: while regular Athlon 64 X2 models are specified to a maximum TDP of 89 W, every processor up to 4800+ will also be available as a low power version. All single cores and the 3800+ X2 dual core will even maintain an impressive 35 W power envelope. These will all be fabricated on 200 mm wafers, based on the current 90 nm SOI process. Although AMD is preparing to switch its manufacturing facilities to 65 nm circuitry on 300 mm wafers, it will take a few months before the firm can output processors in volume using this newer technology.
The introduction of the Socket AM2 platform will also change the current cooler specification, forcing the cost of a new thermal solution on those Socket 754/939/940 folks willing to upgrade. The change does not affect the maximum dimensions of the mounting frame, nor the cooler, but it redefines the clamping mechanism. This is no issue for the big players (system integrators and OEMs), but enthusiasts might have to throw their existing high-end cooling solution out of the window.
We were able to install a simple Socket 939 cooler, which should be possible with some products that are around. However, any cooling solution that has to be screwed directly to the motherboard definitely cannot be used any more, as there are now four rather than two mounting holes. Still we hope that high-end cooler vendors will offer modified mounting kits for their premium products.