HI, My current setup - AMD Phenom 965, Asus 250GTS 512mb TOP, 4GB(2x2GB) ddr2 Corsair Dominator Ram, and 550w Odin GT PSU. Will this be powerful enough to support an additional 250GTS in sli or must I upgrade my PSU - Im considering the 800w Odin GT PSu (Is it any good??) Thanks