Filtering Performance Comparisons



 640x480 800x600 1024x768 1280x1024 1600x1200
Bilinear 148.3 145.2 139.1 124.8 102.8
Trilinear 149.7 145.2 137.0 108.6 82.5
Diff From Bilinear 640x480 800x600 1024x768 1280x1024 1600x1200
FPS 1.4 0.0 -2.1 -16.2 -20.3
% 1% 0% -2% -13% -20%

As we can see, as the resolution increases there is a reasonably large performance difference between Bilinear and Trilinear sampling, to the tune of 20%. This is a good indication that each of the texture sampling units are only Bilinear sampling units and require both at the same time to perform full Trilinear filtering.

8x Quality 640x480 800x600 1024x768 1280x1024 1600x1200
5800 Ultra 149.8 140.8 113.2 82.4 62.1
5900 Ultra 149.7 141.7 112.8 83.3 62.8
Diff from 5800 640x480 800x600 1024x768 1280x1024 1600x1200
FPS -0.1 0.9 -0.4 0.9 0.7
% 0% 1% 0% 1% 1%

Whereas the 5900 Ultra opened up a little gap on the 5800 Ultra in the normal rendering test under this SS:SE demo, with 8x Anisotropic Filtering the 5800 Ultra managed to claw that deficit back a little. Because Anisotropic filtering requires many texture samples to be taken this is quite a fill-rate intensive task and so it's likely that the extra clockspeed, hence fill-rate, that the 5800 has in comparison to the 5900 allows it to reduce the difference between the two boards.