Results: DiRT 3
Codemasters has probably the best looking racing games on the planet. They pulled out all stops with DiRT 3. This particular title features plenty of DX11 effects and tessellation (though I think they took a step back with water effects as compared to DiRT 2). The game used the Ultra preset with 4X AA and 16X AF enabled. The built in Aspen benchmark is used.
The N580GTX had a strange hiccup at 1680×1050 in that it dropped the min framerate far below the others. Going up in resolution actually helped this situation. NVIDIA has a pretty hefty advantage in DiRT 3, and it shows with an outstanding performance from the N580GTX. That card nips at the heels of the R7970 and completely overtakes the R7950.