Sorry peeps, gotta pipe in again and defend lower-spec systems. I have consistently had certain 3D fighters working fine as low as 2Ghz using older builds of MAME, when the emulation core was less mature. Using the correct display and frameskip settings, I had Tekken 1 running fine as well as SF EX. Also I've had N64 and even PS1 running sweet as low as 1.6Ghz, though found 1.8Ghz is better, so sod 3D fighters in MAME as the PS1 had many of them ported over, with more characters, versus modes and more features. Oh, and the systems I'm talking about don't have massive RAM or additional graphics/sound cards either, just average on-board NVIDIA graphics. My minimum spec to run what I've mentioned would be 1.6Ghz with 256mb RAM, but I'd say it all runs just great for what is worth playing at 2.4Ghz with 1GB RAM - just optimise Windows and use a pre-0.106 build of MAME.