Aliens vs. Predator
The standalone Aliens vs. Predator benchmark uses DX11 features such as hardware tessellation and advanced shadow sampling to draw and animate everyone's favourite xenomorph.
More of the same in Aliens vs. Predator. It's only smooth at 1,680x1,050, however. Comparing default clocks, HD 6870 sits between the GTX 470 and GTX 465 cards, while the HD 6850 is a touch slower than GTX 465.