I just noticed something interesting with the Doom 3 benchmarks in the THG and HardOCP articles.
GeForce FX 5900 Ultra
Medium Quality, 4x AA, no AF (from THG -
http://www6.tomshardware.com/graphic/20030512/geforce_fx_5900-13.html)
1024x768 - 57.1 fps
1280x1024 - 38.1 fps
1600x1200 - 27.7 fps
Medium Quality 4x AA, 8x AF (from HardOCP -
http://www.hardocp.com/article.html?art=NDc0LDI=)
1024x768 - 57.2 fps
1280x1024 - 38.1 fps
1600x1200 - 27.6 fps
Notice how the scores are within 0.1 fps of each other, despite 8x AF supposedly being enabled in the second set of tests. Both sites used P4 3.0GHz CPUs.
Radeon 9800 Pro
Medium Quality, 4x AA, no AF (from THG -
http://www6.tomshardware.com/graphic/20030512/geforce_fx_5900-13.html)
1024x768 - 43.3 fps
1280x1024 - 29.2 fps
1600x1200 - 17.3 fps
Medium Quality 4x AA, 8x AF (from HardOCP -
http://www.hardocp.com/article.html?art=NDc0LDI=)
1024x768 - 37.8 fps
1280x1024 - 26.2 fps
1600x1200 - 16.5 fps
Notice how the 9800 scores significantly lower with AF enabled, as would be expected.
This begs the question of whether AF was being correctly enabled on the GeForce FX cards in the Doom 3 previews. Given how much this game stresses the gfx hardware, it seems highly unlikely that there would be no performance impact whatsoever for enabling 8x AF.
Even more interesting is the news that the High Quality mode in Doom 3 enables AF from within the app. Only THG ran benchmarks in this mode - and in those benchmarks the 9800 Pro matched or outperformed the 5900 Ultra.
If it is true that AF was not actually being enabled on the GeForce cards for the tests (whether by cheat, driver bug, or game bug), but it was correctly enabled on the Radeon cards, then a good portion of the Doom 3 benchmarks we saw posted would be grossly inaccurate. In fact, only the High Quality tests on THG would give a legitimate picture of relative performance with AF - and if all the test results looked like that, I think the conclusions drawn by the articles would have sounded much different than they do now. Especially considering that anyone who pays $300+ for a gfx card these days is going to expect to keep AF on all the time.
Pity no one was allowed to take screenshots to prove whether or not AF was getting correctly enabled... but I guess we now know why Nvidia might have wanted it that way!