I actually played through Quake4 and Doom3 not even a month ago and didn't have such problems. Yeah I know it's no help for you but just saying. 
C2D E6750 @ 3.2Ghz, 4GB 800MHz DDR2 4-4-4-12, GeForce GTX 260 c216 OC 896MB, 3.2TB, Windows 7 Ultimate x64
Xbox 360 Elite, PS2 Slim, Xbox