Prior to the game's release, the developer put out a benchmarking tool to test your system configuration. It offers a number of different options for utilizing DX9, 10 or 11 code paths. It also offers options for varying levels of HDAO and Shadow Quality. The demo itself isn't very pretty to look at (lots of dirt and dirt-colors), but it does put a beating on your system.
Like the Heaven demo, the demo basically will not run at 5760x1080 using 4xAA, with only 1GB of VRAM. The 2GB card Eyefinity6 card does run the demo, though it proves to be quite demanding. 5x1600x900 performs on par with either 3x1-L setup, though 5x1920x1080 brings the CFX setup to its knees.