San Diego brings SSE3 support to Athlon 64 FX for the first time, along with support for mismatched DIMM sizes in its memory controller, more efficient use of memory compared to Clawhammer and more performance from its data prefetcher, which pulls data out of system memory into the processor's caches, in advance of it being needed.

A lower supply voltage likely means a BIOS update for the majority of boards and board vendors will likely roll in FX-57 BIOS support with their Venice and Toledo 90nm changes. Basically a Clawhammer at 2800MHz with SSE3 and some memory controller and prefetcher tweaks, using around eight million more transistors to get there.