DDR2 has been around for awhile now. The speed of DDR2 will soon be 667. When will AMD start using it? Is there any technical issue with the memory or the CPU?

ddr2 667 is about as fast a ddr400, this is pretty much the break over point where there is an ACTUAL advantage to using it, having said that current athlon64's are not really starved for memory bandwidth so holding off their release until ddr2 prices comes down to reasonable levels is a good thing in my book.

I think the first ddr2 amd 64 chips are slated for next year (dual core/mobile), so don't hold your breath. (source dodgy enquirer/xbit articles)