Quake 4 is a follow-up for the Quake II based on the Doom III engine. There are a number of differences between the Quake 4 and the Doom III, though: the former has more realistic design thanks to more complex geometry and more lighting effects in addition to some other improvements. Generally, the Quake 4 looks much better than the Doom III, but it still has some headroom for evolution.
High-End Graphics Cards
While the Quake 4 game is graphically intensive, all expensive graphics cards today manage to deliver awesome framerate here. In fact, in 1024x768 resolution the system itself appears to be a limiting factor as the speed is in the range of 115fps across all cards.
Even with eye candy enabled, all the graphics boards among the high-end camp succeed in delivering enough speed with full-scene antialiasing and anisotropic filtering enabled. It is interesting to note that thanks to more complex geometry and higher amount of pixel shaders among comparable graphics cards from ATI and NVIDIA products from the former manage to leave the GeForces behind. The exception is the GeForce 7800 GTX 512 that is faster compared to the RADEON X1800 XT 512MB.
In brief, of you are looking for the fastest Quake 4 solution possible, pay attention to the GeForce 7800 GTX 512.