S.T.A.L.K.E.R.: Call of Pripyat uses version 1.6 of the X-ray Engine to provide full DirectX 11 support. Each graphics card was tested using the highest possible level of DirectX. This meant that the Radeon HD 5000 series cards were tested using DX11, and while the GeForce GTX 295 managed just 37fps at 2560x1600, the Radeon HD 5970 cranked out 68fps, making it a staggering 84% faster!