Aliens vs Predator uses many DirectX 11 features for cards that can support them. This includes tessellation, like the other DX11 games tested, and other lighting and anti-aliasing effects. With all settings maxed out, the Double Black Diamond 7870 plays smoothly. This also includes some of the more intensive scenes which make the 7870's little brother, the Radeon HD 7850 struggle. However, the GeForce GTX 580 pulls ahead of all the other video cards by a fair margin.
It's the same story when disabling AA. The Double Black Diamond 7870 performs well, but far behind the GeForce GTX 580.
S.T.A.L.K.E.R. Call of Pripyat uses the XRAY 1.6 game engine which offers a wide range of DirectX support, version 8 through 11. It does support tessellation and its implementation results in a lot of realistic looking buildings and scenery. And to help create a scary ambiance, lots of dynamic lighting effects are used. Maxing out all of the settings, Diamond's Radeon HD 7870 is near the top, with only the GeForce GTX 580 ahead.