Tommti-Systems' FSAATest program is an excellent utility for revealing the effectiveness of an antialiasing algorithm under Direct3D. Our interactive comparison page has been updated and now contains results from the antialiasing modes that are available on the GeForce 6800 Ultra. A useful program for advanced image quality comparison analysis is The Compressonator, which is capable of highlighting the differences between two images.
Interactive Antialiasing Comparison
The antialiasing modes that are exposed through the 60.72 beta ForceWare drivers for the GeForce 6800 Ultra consist of 2X, 2xQ, 4X, and 8X. Making use of the antialiasing comparison reveals that 2X, 2xQ, and 8X, which is actually 8XS on the GeForce FX, appear to have been carried over from the GeForce FX. However, the quality of the 4X mode has been improved.
ForceWare 60.72 Antialiasing Settings
Based on NVIDIA's documentation, the GeForce 6800 employs a four-sample rotated-grid multisampling (RGMS) algorithm for antialiasing compared to the GeForce FX's ordered-grid multisampling (OGMS). The subpixel coverage of the rotated-grid pattern will provide increased color accuracy over the ordered-grid pattern when determining the final output color of a pixel. The subtle difference in colors that are applied using RGMS will result in a smoother edge appearance under most conditions.
3DMark03 Image Quality Test
The following images were copied from a section of the 3DMark03 image quality test results at frame 1100 in Wings of Fury. The test was conducted at a resolution of 1024x768 with application controlled 4X antialiasing and application controlled 8X anisotropic filtering. These images illustrate that the effectiveness of 4X antialiasing on the GeForce 6800 Ultra exceeds that of the GeForce FX 5950 Ultra and is a close match to the Radeon 9800 Pro, which also uses RGMS.
4X Antialiasing - Normal Size
GeForce FX 5950 Ultra
GeForce 6800 Ultra
Radeon 9800 Pro
These images have been enlarged 100%, which gives us a better look at the pixel colors that were generated under each method of antialiasing.
4X Antialiasing - Enlarged 100%
GeForce FX 5950 Ultra
GeForce 6800 Ultra
Radeon 9800 Pro
A forum discussion on this comparison can be found in this thread.
Frame 1100 contains a number of edges that are positioned at various angles. This comparison provides a better chance of finding minor variations between the 4X antialiasing on the GeForce 6800 Ultra and the Radeon 9800 Pro.
4X Antialiasing - Normal Size
GeForce 6800 Ultra
GeForce FX 5950 Ultra
Radeon 9800 Pro
Again, the 4X antialiasing quality of the GeForce 6800 Ultra and Radeon 9800 Pro is very close. Subtle differences do exist, although it is unlikely they will be noticable during gameplay situations.
4X Antialiasing - Enlarged 100%
GeForce FX 5950 Ultra
GeForce 6800 Ultra
Radeon 9800 Pro
Another antialiasing test I conducted was to observe the Wings of Fury benchmark running on both graphics card with 4X antialiasing enabled at various resolutions. Each graphics card was installed in a seperate PC, which were near one another. I found no noticable differences between the GeForce 6800 Ultra and Radeon 9800 Pro in the severity of the "texture crawling" effect that appear along edges during motion. While this effect was still noticeable at a resolution of 1600x1200, it was virtually eliminated at the ultra-high resolutions of 1920x1440 and 2045x1536.
The full size 3DMark03 images rendered by each graphics card can be viewed by clicking the corresponding link below:
A forum discussion about this comparison can be found in this thread.
Lock On: Modern Air Combat
The following comparative images between the GeForce FX 5950 Ultra (NV35) and the GeForce 6800 Ultra (NV40) were taken from the flight sim Lock On: Modern Air Combat at a resolution of 1024x768 and enlarged 100%. The first image is used to specifically illustrate the improvements in the antialiasing quality of the GeForce 6800 Ultra along edges that are positioned in a predominately horizontal or vertical direction.
4X Antialiasing - 100% Enlarged
The second series of images are of similar quality with the exception of the bottom of the semi-circle, which has a smoother looking appearance on the GeForce FX 5950 Ultra.
4X Antialiasing - 100% Enlarged
The images below are also similar although the black colored line to the left of the letters SP looks better on the GeForce 6800 Ultra as does the edge of the object to the left of the line. The edges on the dark object that covers much of the left side of the picture are also slightly better looking on the GeForce 6800 Ultra.
4X Antialiasing - 100% Enlarged
Dungeon Siege
Dungeon Siege is a personal favorite and I was very pleased with the results that 4X antialiasing on the GeForce 6800 Ultra provided. Both closeups of the player model are based on in-game screenshots that were captured at a resolution of 1024x768.
No Antialiasing vs. 4X Antialiasing
No Antialiasing
4X Antialiasing
Many of the edges, such as those along the bow, arrow, and character outline, are noticeably smoother. The top of the left arm and intersection of the green ring with the left boot, both of which are positioned at a 160° angle, appear less smooth.
The new 4X antialiasing algorithm is a welcome addition to the GeForce 6800 Ultra feature set as the ordered-grid pattern that was used on the GeForce 4 and GeForce FX was ineffective in many situations. While the hybrid multisampling (MS) and supersampling (SS) antialiasing modes NVIDIA developed for the GeForce FX improved edge quality, they often resulted in too much of a performance hit to be widely used. The performance hit of 8X antialiasing, which is based on a combination of MS and SS, remains significant on the GeForce 6800 Ultra.
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