原文出處:
http://english.bonusweb.cz/interviews/carmackgfx.html

John Carmack about GeForce FX and DirectX 9

In view of recent ATI’s Shader Day event and Gabe Newell’s presentation of
Half-Life 2, we asked John Carmack about his opinion. What can we expect
from GeForce FX family regarding future DirectX 9 games?

--------------------------------------------------------------------------------

Hi John,

No doubt you heard about GeForce FX fiasco in Half-Life 2. In your opinion, are
these results representative for future DX9 games (including Doom III) or is it
just a special case of HL2 code preferring ATI features, as NVIDIA suggests?

Unfortunately, it will probably be representative of most DX9 games. Doom has a
custom back end that uses the lower precisions on the GF-FX, but when you run it
with standard fragment programs just like ATI, it is a lot slower. The precision
doesn't really matter to Doom, but that won't be a reasonable option in future
games designed around DX9 level hardware as a minimum spec.

John Carmack