Though it's closing in on two years old, the AvP stand-alone benchmark tool is still a good test of DX11 hardware. It isn't very demanding from a CPU perspective, so it gives a good test of the GPU itself.
The AvP demo also makes good usage of DX11 effects such as Advanced Shadows and Geometry Tessellation, particularly on the alien creature and the alien "pods". There are also some unique lighting effects created with a mobile lighting sources in a floor lamp that is battered around by the alien creatures as they clamor down a tight hallway.
In widescreen, the GTX 670 bests the Radeon HD 7950 by a few frames. Conversely in multi-monitor the Radeon HD 7950 bests the NVIDIA GTX 670 by a few frames.