you may get a 550 ti on sale about $110. try using this performance chart . http://www.geforce.com/Hardware/GPUs/geforce-gtx-590/performance or you can try finding a second 250 and run in sli, if you mb supports it. im running 2 gtx 275

ya try the game in windows. I7 920 oc at 3.9 running dual gtx 275 . both cards running at 84-94 % gpu usage 70- 110 fps