Meh, I don't quite understand this either. I've got a completely opposite problem. While Carbon didn't want to run smoothly even on the lowest details and lowest res, Pro Street runs smoothly on highest details and 1280x800 res. I think it could be something to do with it being optimized for Vista and newer graphics cards? Rather a good game though. Edit: that's on a X2 6000+, 3gb 667mhz memory and 8600GT card. You don't need a quad core with SLI graphics for it to run.