Looking for the best

[linkdead14]

This is my first post, I appreciate any replies. Today I received my GTX 280 in the mail. I installed it and it seems my CPU is really bottlenecking the video card. Right now I have an AMD X2 4400 on my GA-M57SLI-S4. I was hoping someone could point me in the direction of the best possible processor I could put onto this board. I read somewhere that I could install a Phenom with a BIOS upgrade, but I also heard it down graded some part of the motherboard to do so.