> But I suppose there's still not enough power to run the more insanely power
> hungry games out there. And i also don't think MAME is capable of utilizing a
> quadcore CPU to it's full extent.
True, there is no processor out there that runs all MAME games full speed.
MAME can optimally use 2 cores in more recent versions. Anything more (4, 8) will not yield substantially better results. You're better off sticking with 2 cores and faster speeds (I.E. 2 Cores at 3.0Ghz as oppose to 4 cores (or more) at 2.4Ghz).
Furthermore, MAME posts fastest/best performance under 64-Bit OS and 64-bit MAME compile.