I use a Radeon 9800 Pro overclocked to 431/371.
I run AH at 1024x768 with 4xFSAA and 8x AF and get 80 average, with the lowest drops being around 45 in heavy action. Quality settings in AH raised slightly.
You will see slightly lower frames because I have a faster CPU and RAM, and because I am overclocking, but you might get away with 6x FSAA and get the same framerate as below because the video card will not be pushed to its max by the CPU.