Doom III traditionally works perfectly on NVIDIA’s GeForce 6 and 7 hardware, which is why the gap between the GeForce 7800 GT and the RADEON X850 XT PE is very large. Performance difference between the former flagship product and the GeForce 7800 GT is not sizeable at all, it should be noted.
Once FSAA and anisotropic filtering are activated, the performance gap between the GeForce 7800 GT and 6800 Ultra shrinks further and neither of them can achieve 60 fps, a level of performance usually considered as minimal acceptable for first person shooter games.
Similar comments can be written for the second demo we use in Doom III: GeForce 7800 GT provides sufficient frame-rate for all resolutions and is tangibly faster than the GeForce 6800 Ultra and the RADEON X850 XT PE.
With FSAA and anisotropic filtering turned on. the GeForce 7800 GT continues to be a very strong performer, even though it does not offer really significant advantage over the former king of the hill this time.