Originally posted by jbirney
I will see if I can find the post from the ATI employee that stated that they thought their AF is fine and just wanted to improve their angle perfromance. I thought I saw it back on B3D from OpenGL guy...Your theory is based off on techincal facts however thats not why ATI chose this method of Aniso (again look at the speed tradeoff this method gives). Also if I remember OpenGL guys this was the same AF that they used in the 8500 just with tweaks (angles and tri-linear).
There is no evidence to support that ATI's aniso method is fundamentally of higher performance.
Quite simply, the GeForce4 does not have the ability to calculate the degree of anisotropic for two textures per clock, which, for most cases effectively makes the GeForce4 a 4x1 card when anisotropic is enabled. This alone is enough to reduce the performance significantly (It can be made a 4x2 card with aniso enabled if anisotropic is enabled only for the second and fourth texture stages...).