This is a note for all you guys out there with cheap ass video cards. This is quite funny, but I installed Doom 3 on my PC, and it works perfectly...NO LAgg, and awesome graphics..
My PC happens to be a P4 2.4 Ghz, 512 MB PC 2700 RAM, an NVidia GeForce 5200 FX graphics card. Before Ocing nething, just make the settings Application controlled, for EVERYTHING, and it works perfectly smooth....!!