I'm actually kinda doubting it's his CPU, I have a P4 2.8 GHz, 1024MB RAM, and a Radeon 9550 256MB. I've got my framerate limited to 100FPS, and I'm pretty much always running against the FPS limiter, even with a full A.I. grid at the start, I still get 45-50 FPS. This sounds like a stupid solution, but make sure that hardware acceleration is turned to full in your display settings, a friend of mine had something like that, he and I tried all the "technical" solutions before going, "duh, hardware acceleration is off." Hope that helps, over and out.
-Ryan