i7 920 x58 Chipset if you have a larger budget, If not any i5 P55 would do fine.
I was hoping for something cheap and just a quick band aid solution that I would say ok and regret later on. All I am doing is running two 9800gt(s) in sli and run pcsx2 with fraps in the background. It just sucks run lost planet at 30~fps or so then turn on fraps and watch it drop down to single digits. Same for crysis 30~60fps then turn on fraps and get 1/5 of what I used to get. With only one card it can record at 20fps fine.