ATI 100 437807 User Guide - Page 38

32 CrossFire™ Rendering Modes 1 Radeon® X1950 Pro Graphics Card 2 Radeon® X1950 Pro Graphics Card 3 Partial Frame Rendered on Radeon® X1950 Pro Graphics Card 4 Partial Frame Rendered on Radeon® X1950 Pro Graphics Card 5 Final Rendered Frame on Display Some types of textures, especially those with transparent portions, can exhibit aliasing that is not removed by MSAA techniques. Another form of anti-aliasing, known as Super-sample Anti-aliasing (SSAA), can be useful in these cases, because it affects every pixel in an image. Although it normally operates more slowly than MSAA, the power of multiple GPUs can make SSAA practical to use. SSAA first renders a scene at a higher resolution than that which is output to the display, which is then downsampled to the display's resolution. This approach normally has two main disadvantages: it requires rendering many more pixels than normal, which can have a drastic impact on performance, and that it results in an ordered grid sample pattern, which does a poor job of anti-aliasing some types of jagged edges. CrossFire™'s Super Antialiasing overcomes both of these problems. It takes advantage of the second GPU to render the additional pixels required for each frame, so there is little or no performance impact. It can also make use of a more effective sample