Hardware

The original requirement of id Tech 4 was that it needed a high-end graphics processing unit (GPU) with fully programmable vertex and pixel shaders, such as the Nvidia GeForce 3 or ATI Radeon 8500, with at least 64 MB of VRAM. By E3 2002, the recommended GPU was "100% DirectX 9.0b compatible", such as the Radeon 9700 with 128 MB of VRAM. While the Radeon 9700's DirectX 9.0 features are not necessary to render the game, its advanced architecture, 256-bit memory bus, and efficiency were needed to run Doom 3 at high detail and playable speed.[6]

id Tech 4 resulted in the obsolescence of DirectX 7 graphics chips such as the widespread GeForce 2 and Radeon 7200, as well as older chipsets such as RIVA TNT2 and Rage 128, and software rendering (with an integrated Intel GMA). Until the advent of id Tech 4, a powerful CPU was able to somewhat compensate for an older video card. While John Carmack initially warned gamers not to purchase the GeForce 4 MX[7] (which casual consumers often confused with the DirectX 8 capable GeForce 4 Ti, though it was at best an improved GeForce 2), its somewhat widespread adoption compelled id Software to add it to the list of supported cards. There have been cases of enthusiasts forcing Doom 3 to run on unsupported graphics chips, such as the long obsolete Voodoo 2, but these are unable to render the per-pixel lighting and bump mappin