Im looking for a graphics card that would be compatible with my pc. My computer is Gateway DX4870-UB17. I want to be able to run fps games. like the ghost recon phantom, bioshock infin, and such. in medium settings 1080p or 720 with decent framerates. my only concern is the power supply being 300W. maybe I can upgrade the power supply also. my budget is about 600$. Help, and many thanks.