The Athlon64 is going to be a nice chip. The 64bit mode cleans up the x86 architecture and make it much nicer (16 visible General purpose regs, 64bit regs, lots of masive ALU and FPU pipes, caches galore, flat memory model, sounds more and more like a 68k on speed ;-) ) (nice to see those ex-Alpha Engineers are being put to good use), but still be able to run old x86 apps transparently.