ATI's SMOOTHVISION - The key to its "success"

ATI vs. NVIDIA: 4X AA Quality

We've already seen what the two cards look like with AA disabled so let's just jump straight into the screenshots (Note: since these screenshots are so small we'd suggest setting your screen resolution to no greater than 1024 x 768):

ATI Radeon 8500 4X Performance AA

ATI Radeon 8500 4X Quality AA

NVIDIA GeForce3 Ti 500 4X Multisampled AA + Aniso

Again we see that it takes the enabling of anisotropic filtering to bring the GeForce3's texture quality up to par, but doing that does the trick as we don't see any clear differences between the texture quality in the three shots from above. We can get some indication of edge AA quality from these shots; if you look at the topmost platform the blurred AA samples in the 4X performance mode appear to be above the stairstep line where they should be. In the 4X quality and NVIDIA's 4X mode the samples appear just fine. Now let's have a look at edge AA quality in Serious Sam:

ATI Radeon 8500 4X Performance AA

ATI Radeon 8500 4X Quality AA

NVIDIA GeForce3 Ti 500 4X Multisampled AA + Aniso

With 4X AA enabled it's much more difficult to tell any difference between the edge AA quality of the three screenshots although it's clear that the performance mode is definitely not as smooth as the quality mode or NVIDIA's 4X multisampled AA.

4X AA Conclusion: With anisotropic filtering enabled, NVIDIA's 4X AA is able to compete with ATI's 4X Quality AA in terms of texture quality and edge AA quality. ATI's 4X performance AA is not as good at anti-aliasing edges as NVIDIA's 4X mode.