Physics card support would probably take a huge load off the processor.

I'm running COH real nice. Nvidea 7600GT 256MB, AMD X2 4200+, 2GB RAM.

I run Day of Defeat: Source at 1024X768 with all eye candy, real smoothly with an integrated 6200. Diablo one and two should've been mentioned.

I like the pseudo-Sin City theme.