the xbox 360 Xenos GPU and anti aliasing..

The Xenos GPU has "a 10 MB eDRAM daughter-die," and because of this it "can do 4x FSAA, z-buffering, and alpha blending with no appreciable performance penalty on the GPU."

(According to http://en.wikipedia.org/wiki/Xbox_ [...] sing_unit)

I was just wondering why they dont put something similar on graphics cards so that we can turn on the AA all the time without losing FPS (especially useful in Crysis I'd imagine). Maybe they already do. I dont know that much about GPU architecture.

Anyone know anything about this?

The 360 is a closed platform and is only required to render at one resolution, usually 720p. It would be much more complicated for a PC GPU to implement an eDRAm type solution since there are so many possible hardware combinations, resolutions, levels of AA, etc.

Also the memory bus architecture of Xenos is much different than the memory buses of PC GPUs.

In short, I believe that eDRAM could be done on a PC GPU, but it would not be an easy thing to accomplish.