"One of the main reasons for the atmosphere being so good is the Doom 3 engine, which was greatly advertised by the developers. As we all have come to expect from id game engines, Doom 3 also takes it's toll on PC resources, with only the latest gaming rigs being able to run it at 1600x1200, with high details and anisotropic filtering and antialiasing activated. And although id declared that only a 512Ram video card can handle Ultra High Quality, that doesn't necessarily mean that the game looks bad on medium or high quality. Although I read the [H]ardOCP [H]ardware Guide that came out last week, I was pleasantly surprised to see the game running with 16 to 40 fps on my XP 2200+, GF4 Ti 4200 with 128 VRAM and 512 MB RAM, on medium quality, with no AA or anisotropic filtering. But I was only able to do so after I stopped all unnecessary services and made some tweaks to my Windows XP."