I Play and use FPSE on my MacMini 1.5GHz and 64MB VRam. GrandTurismo 1 and 2, ColinMcRae2.0, SoulBlade have nice play speed. Tekken3 is litle bit to slow.
I play in this games from CD and on window (not full screen). I didnt try play from ISO.
I found Tekken3 ISO 40mb and work nicer...