The new 8x, 12x and 16x Anti-Aliasing on GeForceFX

April 13, 2003 / by aths & Leonidas, translation by Zeckensack & nggalai / page 3 of 6

   Direct3D Performance

First, we'd like to present some performance numbers before drawing any conclusions. We used Unreal Tournament 2003's Flyby on CTF-Face3 at 1024x768x32 and maximum quality settings, because this benchmark is available for both Direct3D and OpenGL, serves as a semi-theoretical test that scales well with graphics performance, and is highly reproducible (we're not really interested in absolute real world performance in this case, instead we're looking for performance differences):

Judging by the numbers it's becoming pretty obvious that the setting called "6xS" in the Detonator control panel is what aTuner calls "6x". Further, nVidia (still) opts for the inferior 8x setting from the 8x anti-aliasing choices. This mode is called "8x" by both the driver panel and aTuner, so at least the naming scheme is consistent here. aTuner additionally offers the higher quality 8xS anti-aliasing setting.

nVidia's naming scheme is completely off regarding what the Detonator panel calls 16x anti-aliasing: This is aTuner's 12x mode - and aTuner is right! This setting - the highest available under Direct3D - doesn't use 16 subpixels, it uses only twelve. The name "16x anti-aliasing" as chosen by nVidia is, unfortunately, misleading.

In principle, nVidia's newly-offered anti-aliasing settings for Direct3D don't make much sense. As has been the case before, 4xS is the most effective anti-aliasing setting for Direct3D. Because of the highly inefficient subpixel positioning, 6x and 8x are both worse in terms of "achieved image quality". 12x cannot be generally recommended because it introduces dithering artifacts along horizontal edges. We suspect that the hardware does not allows the required 1/12th weighting of subpixels and instead alternates 1/8th and 1/16th weights. To wrap it up, 4xS is (obviously) faster than 6x, 8x or 12x, and it still achieves superior edge smoothing.

Only a true 8xS mode can exceed the image quality of 4xS. 8xS is supported by the drivers, but it cannot be activated through the Detonator control panel. aTuner gives users in need of the highest possible image quality the choice to still use this setting. The downside is 8xS's severe performance impact, making it viable only for high-end graphics cards and a small selection of games.