Originally posted by Spiritwalker
Just to refresh your memory, Doom]l[ is an OpenGL game NOT a DX9 game so you cannot make the comparison.
That and the fact that JC has specifically coded the game for the nV30.
There are 5 paths for the Doom3 to render only one of which is NV30 specific. There is one that was coding for the R8500 as well. This path that the 8500 uses the OpenGL version of PS1.4.