Benchmark Results: Crysis
Yes, both cards can play Crysis all the way up to 1920x1080 with Very High details and 4x AA. Expect to lose 10% from either card by dropping it in a x4 slot, while the x8 slot gives up only 2-3%.
Though our average frame rates are charted for easy comparison, we often refer to a minimum frame rate of 20 FPS when discussing playability. That’s not possible from either the GeForce GTX 570 or Radeon HD 6950 at 2560x1600.
Note that the performance drop due to switching from a x16 to an x4 slot falls to 6% for Nvidia. AMD still suffers a loss of nearly 10%, even at this GPU-bottlenecked setting.