ATi & nVidia Anti-Aliasing Performance
Anti-Aliasing quality and performance compared while using anisotropic filtering

Dezember 10, 2003 / by Leonidas / page 2 of 10 / translated by 3DCenter Translation Team

   nVidia Anti-Aliasing Modi

There are a lot more anti-aliasing modes on NV3x (GeForceFX 5200/5600/5700/5800/5950) and - using the right drivers and tools - the NV2x family (GeForce3 /Ti and GeForce4 Ti). Available anti-aliasing modes may differ from one driver version to the next, even with GeforceFX cards. We used driver version 45.23 which obviously isn't the most recent one, but it offers all anti-aliasing modes we wanted to use.

As nVidia never exposed all possible anti-aliasing modes through the control panel, and because the Californian chip designers sometimes rename modes, we'll stick to the naming scheme used by our own aTuner. nVidia uses the following sampling grids and achieves the respective image qualities, again determined with the FSAA Tester tool (clicking on a thumbnail opens a larger image). We skipped the "Quincunx" and "4x 9 tap" modes as usual, because they additionally blur the image.

Modes	Notes	Subpixel Grid	Image Quality
without AA	-	-
1x2	supersampling ordered grid EER 1x2
2x1	supersampling ordered grid EER 2x1
2x	multisampling rotated grid EER 2x2
4x	multisampling ordered grid EER 2x2
4xS	multi/supersampling hybrid partially rotated grid EER 2x4 (Direct3D only)
4xSS	supersampling ordered grid EER 2x2 (Direct3D only)
6x	multi/supersampling hybrid ordered grid EER 3x2 (Direct3D only)
6xS	multi/supersampling hybrid paritally rotated grid EER 3x4 may produce artifacts (Direct3D only)
8x	multi/supersampling hybrid ordered grid EER 4x2 (Direct3D only)
8xS	multi/supersampling hybrid partially rotated grid EER 4x4
12x	multi/supersampling hybrid ordered grid EER 3x4 (Direct3D only)
16x	multi/supersampling hybrid ordered grid EER 4x4 (OpenGL only)		this mode is OpenGL only, so there's no comparison screenshot

The multitude of nVidia's anti-aliasing modes unfortunately doesn't imply that there are more choices that actually make sense. The Quincunx and 4x 9-tap modes are thrown out due to the additional blurring, the latter mode has also been removed from the series 50 drivers. Also dubios is the 6xS mode because it tends to produce artifacts. The 6x mode has been removed from the drivers while 6xS with its issues remained, but note that nVidia call this mode "6x" in the control panel.

Also missing from the series 50 drivers is the 8x mode. This isn't a big loss because the mode isn't competitive in it's smoothing effect due to its ordered sampling grid. That's in contrast to the 8xS mode, which, ironically, nVidia expose in the series 50 drivers instead of the old one, under the same "8x" name (for OpenGL there has only been the 8xS mode anyway). New additions to series 50 are the (rather uninspiring) supersampling modes 1x2 and 2x1.

The 16x anti-aliasing mode for OpenGL has only been in the drivers for a short time, even with driver version 45.23 we used here it didn't work anymore. This isn't a huge loss either because, as we are going to see, even 8xS puts tremendous strains on the nVidia cards and the further improvement in anti-aliasing quality that could have been achieved with the 16x mode would only have led to frame rates completely inadequate for gaming.

So we're left with the following sensible anti-aliasing modes on nVidia hardware: 2x, 4x, 4xS, 4xSS, 6x, 8x, 8xS and 12x, where the 8x mode is only supported by series 40 drivers. Out of these modes, 4xS, 4xSS, 6x, 8x and 12x are also only available for Direct3D.