The FSS part of NVIDIA GeForce FX 5900 Ultra is hardly that much different from what we saw by its predecessor.
That is why I decided to check only the quality of polygon borders smoothening in case of 2, 4 and 8 samples. The screenshots were taken in Serious Sam: The Second Encounter for OpenGL and Direct3D:
Here are enlarged fragments for your convenience. The top row stands for 2x, 4x, 8x in OpenGL, and the bottom row – for 2x, 4x, 8x in Direct3D:
For a better comparison have a look the quality provided by SMOOTHVISION 2.1 2x, 4x and 6x by ATI RADEON 9800 Pro:
It is evident that only 8x mode from NVIDIA can compete with ATI’s 4x and 6x modes more or less successfully.
By the way, it would be more correct to say “modes” instead of “mode”, because you can clearly see from the screenshots that 8x in OpenGL and 8x in Direct3D are different modes providing different polygon borders smoothening quality. And since these modes combine supersampling and multi-sampling, not only the polygon borders smoothening will be different, but also textures processing.
To prove this point here are a few more screenshots from Serious Sam: The Second Encounter:
These are a few larger image fragments with enabled 8x full-screen anti-aliasing in OpenGL:
And now the same fragments with enabled 8x full-screen anti-aliasing in Direct3D:
The screenshots shoed that the textures are much clearer-cut in OpenGL 8x FSAA.
If you look at the leaves of the tree created with the help of transparent textures, you will see that in case of OpenGL 8x anti-aliasing they were formed by 2x2 supersampling, while in Direct3D 8x anti-aliasing only 2x1 supersampling was involved.
Summing up our observations I would like to illustrate 2x, 4x and 8x anti-aliasing modes by NVIDIA GeForce FX 5900 Ultra with the following scheme:
The most “advanced” anti-aliasing mode is offered by OpenGL 8x: here we have supersampling of four 2x multisampling blocks. This is cool, and beautiful! :)