DriverHeaven has a writeup on Shader Model 2.0b compatibility with ATI graphics cards. They look at the the instancing feature by which large numbers of the same object can be calculated together instead of independently, thereby increasing performance. An example of this would be the trees in Far Cry. It might surprise you as much as it surprised me because this is one feature Nvidia has talked much about in the new line-up of graphics cards but what I did not know was that ATI supported it also. See this news post on Driver Heaven or go directly to this forum thread.