A couple of separate sources have told us that the R600 might feature free FSAA and AF in some modes. We don't have a lot of details, but at some resolutions and settings you should not see any real penalties when you enable FSAA and AF. That is why we call it "free".

The Xbox 360 Xenos chip can do this with 4X FSAA and 8X Anisotropic filtering if we remember correctly. The R600 secret must lie in the 512 bit memory controller.

Xenos has 10 MB of embedded memory that helps it do the free 4X FSAA and maybe the R600 can benefit from its ultra fast 512 bit memory controller and its fast memory. We still don’t think it is fast enough.  

We are still not one hundred percent convinced and you need to take this with a grain of salt.