Benchmark Results: DiRT 2 And S.T.A.L.K.E.R.
Armed with two Radeon HD 5850s, even taxing DirectX 11 features like tessellation aren’t a problem. This is definitely not the case when it comes to a single graphics card running DiRT 2 in DirectX 11 mode--our recent performance analysis showed that even the mighty Radeon HD 5870 can only manage about 30 frames per second at 2560x1600 when 4x AA is applied.
S.T.A.L.K.E.R. shows a performance increase with the overclock, but it only makes a practical difference at 2560x1600 at ultra-high details with 4x AA applied. At all of the lower settings and resolutions, the game performs so smoothly that any overclocking increases are academic.