The highly anticipated game S.T.A.L.K.E.R. makes use of a proprietary DX9 game engine, dubbed "X-Ray" by its developers. It features an advanced DX9 renderer with Defferred Shading capabilities, which allows the engine to draw a vast amount of dynamic light sources with correct materials and light ‘feedback’. Becuase S.T.A.L.K.E.R. does not have a built-in benchmarking tool, we tested the game using FRAPS at resolutions of 1,280x1,024 through 2,560 x 1,600 with the in-game anti-aliasing and anisotropic filtering options set to their maximum values, and with full dynamic lighting enabled. We should also note that 'grass shadows' were disabled due to the dramatic slowdowns this feature causes during gameplay.
S.T.A.L.K.E.R. @ 2,560 x 1,600
At the settings we used to benchmark S.T.A.L.K.E.R., the game's performance is heavily determined by pixel shader performance at the lower resolutions. As such, the GeForce 8800 Ultra is only marginally faster then the GeForce 8800 GTX until we hit the XHD resolutions, but it was way out in front of the Radeon X1950 XTX in every configuration.