That may be true, but can you explain to me why the Doom 3 alpha ran much faster on a Radeon 9800 than a GFFX 5900 and how the 9800 has all sorts of problems running the closer-to-final game? Is it not because Carmack is still sending nVidia updated versions of the unfinished game so they can "optimise" (disable features for better preformance) their drivers while leaving ATI out in the cold?
BTW, the GF/Detonator drivers, after about v. 29, won't let you play the Doom 3 alpha. Lot of back-scratching going on, methinks.