Which graphics card is better the Nvidia 1.8 gtx 260 or the Ati radeon hd 5770?

i'll be using two monitors and playing games like crysis,sniper ghst warroir, and maybe hawx, it would go in an Hp HPE 310t|||They are about equal in performance. However the 5770 uses less power and supports DX11. If you can afford a little more then look at the ATI 5830 or Nvidia 460 (1GB)