Full-Scene Antialiasing

Just like in case of anisotropic filtering, full-scene antialiasing (FSAA) methods differ from GPU developer to GPU developer, as both try to offer the best speed and quality with their products. When it comes to the GeForce 7950 GX2 and the Radeon X1950 XTX, then the former has much broader choice of FSAA modes than the latter, as the model 7950 GX2 is basically an SLI-tandem, thus, supporting appropriate FSAA patterns.

The list of antialiasing patterns for the top-of-the-range graphics cards from ATI and Nvidia looks as follows:

• ATI Radeon X1950 XTX: 2x, 4x, 6x;
• Nvidia GeForce 7950 GX2: 2xQ, 2x, 4x, 8xs, SLI AA 8x, SLI AA 16xs.

The GeForce 7950 GX2 offers a very wide variety of FSAA modes from which users can choose an appropriate one. In fact, there are so many modes that not a lot of gamers will be able to try them all out. Moreover, there are pretty interesting 8xs and 16xs modes, which are hybrids between multi-sampling and super-sampling that offer increased quality of tiny details. Unfortunately, they are pretty much performance hungry, as you can see from performance numbers further in the article.

ATI Radeon X1950 XTX vs. Nvidia GeForce 7950 GX2 FSAA Quality Comparison
Half-Life 2: Episode One
	ATI Radeon X1950 XTX	Nvidia GeForce 7950 GX2
0x FSAA
2x FSAA
2xQ FSAA	-
4x FSAA
6x FSAA		-
8x FSAA	-
8xs FSAA	-
16xs FSAA	-

After checking numerous screenshots and after comparing them using The Compressonator software (even though it was designed for other purposes, it suits for comparing images perfectly), which allows pixel-to-pixel comparison easily, we can make the following conclusions:

• Nvidia’s 2xQ (MSAA 1x2, also known as Quincunx) it the lowest quality antialiasing today. While it does smooth edges, textures become really blurry sometimes.
• ATI’s 2x MSAA mode is a little better than Nvidia’s 2x MSAA;
• 4x modes for ATI and Nvidia offer more or less equal image quality.
• ATI’s 6x mode is better than Nvidia’s 4x, but is not as good as Nvidia’s SLI AA 8x, even though, the latter is a little bit more blurry than ATI’s 6x.
• Nvidia’s SLI AA 8x is not as good as the 8xs, which is basically the best now.
• It is not obvious that SLI AA 16xs is better than the 8xs.

ATI Radeon X1950 XTX vs. Nvidia GeForce 7950 GX2 FSAA Quality Comparison
Elder Scrolls: Oblivion
	ATI Radeon X1950 XTX	Nvidia GeForce 7950 GX2
0x FSAA
2x FSAA
2xQ FSAA	-
4x FSAA
6x FSAA		-
8x FSAA	-
8xs FSAA	-
16xs FSAA	-

Considering the fact that ATI and Nvidia produce roughly similar 4x FSAA, we believe that it is fair to use equal 4x settings for both.