The aging Doom3 engine gives both the 2600 XT and 8600 GT a strong showing, even at resolutions up to 1600x1200. And while the engine is aging, it is still quite relevant when you consider it will be used as the backbone of the upcoming Quake: Enemy Territory title.
The 8600 GT has a bit more oomph in the lower resolutions, but that advantage diminishes as the resolutions grow. Considering that LCD screens are by and large limited to 60 Hz, anything more than 60 fps probably isn't that noticeable. At a resolution of 1600x1200, the 8600 GT is still leading by 7 fps, but both cards are providing great playability. Let's see if the story stays the same when anti-aliasing and anisotropic filtering are enabled:
This was a little unexpected, as traditionally the 8600 GT is a stronger performer than the 2600 XT when AA and AF are used. In any case, the 2600 XT's advantage is slight, although it might be noticeable at the 1280x1024 resolution.
The 2600 XT has made a strong showing so far, despite its slower memory clock speed. Let's see if this trend holds up in the first person shooter, F.E.A.R.