S.T.A.L.K.E.R.: Call Of Pripyat
Just like Metro 2033, the DirectX 11-enabled S.T.A.L.K.E.R. is heavily dependent on the graphics card.
A single-core CPU gets overwhelmed, but a second core, despite helping slightly and generating a few more frames per second, hardly gets used at all. A quad-core CPU fails to bolster performance, though overclocking offers a bit of improvement. Focus on the graphics card and consider using at least a dual-core CPU. Graphics memory is completely maxed out at 762 MB with AA activated.