That archetecture was created with DX10 in mind, but M$ changed it because nVidia already had its cards out, the 8800GTX/GTS. Those cards, and every nVidia card made since then isnt capable of the DX10 (now DX10.1) implementation of AA thru their hardware, thats why AC pulled the DX10.1 and went backwards to just plain old DX10, which gave nVidia an advantage in that game. A game in which youll find on it, The Way its meant to be played (damn progress, full retreat ahead)