Here's another look at NVIDIA's new SLI AA, this time by Elitebastards:
As we've already hinted at in our introduction, the basic theory behind SLI anti-aliasing is a very simple one. In a normal SLI configuration, two video cards are put to work as a team in an attempt to double rendering performance - This is achieved either by each card rendering every other frame in the scene (i.e. GPU one renders the first and third frames, GPU the second and fourth), known as AFR or Alternate Frame Rendering, or by splitting each frame in two and giving a certain portion of the frame to each board, known as SFR or split-frame rendering. The intricacies of these methods are best left for another day, but that's the basic principle.