I own a system that can run Crysis in High settings and other Unreal Engine games like BorderLands smoothly (Radeon 4670 with 1GB of dedicated memory, Dual Core 2,4 Ghz, 4GB or RAM) and other games like Just Cause 2, and yet this one overheats my graphics card and make the game slow, even during the splash screens! As of now, if you're in need of a modern old-school shooter, I advise you to try Serious Sam 3, with which I've never had any issue. I might change my review if these issues get solved later.
