Anisotropic texture filtering quality

16X anisotropic filtering - Radeon 9800 XT

16X anisotropic filtering - Radeon X800 XT

16X anisotropic filtering - GeForce 6800 Ultra - 60.72 drivers - Optimizations disabled

16X anisotropic filtering - GeForce 6800 Ultra - 61.11 drivers - Optimizations disabled

16X anisotropic + "brilinear" filtering - GeForce 6800 Ultra - 60.72 drivers - Optimizations enabled

8X anisotropic filtering - GeForce FX 5950 Ultra

With colored mip maps and aniso filtering, the differences become very clear. With optimizations disabled, NVIDIA's 60.72 drivers did filtering almost exactly equivalent to ATI's, but the 61.11 drivers do something less than that, though the degree varies depending on the angle of the surface.