AFR is the fastest mode available, as each frame is rendered by one card at a time. The first card renders the odd-numbered scenes and the second renders the even scenes. Unlike the SuperTiling and Scissor modes, where both cards had to do the geometry for each scene, AFR allows each card to only focus on one half of the work. Each card only has to deal with the geometry and shading on its frames.
Again, with every pro there is a con, of course. Many games use special features that are collectively called dynamic texturing. These effects include volumetric fog, cube effects used in reflection and specular highlighting, procedural texturing, and dynamic normal map generation - features needed for almost everything in today's games. Without render-to-texture effects, dynamic texturing is not possible and games lose all of what makes them amazing to look at.
ATI also offers one other technique called Super AA Mode, but it is not intended to make your games faster - instead, its goal is to make them look better. SuperAA is the culmination of two sets of sampling patterns, with the first card sampling one way and the second another. The compiling chip takes both information sets and combines the images into one.
Theoretically, this mode offers the speed of 4XAA while delivering the quality of 8XAA. In June, ATI announced that the FSAA patterns on Radeon X8xx cards are freely programmable. Therefore, CrossFire models do not use different FSAA patterns than those of the standard Radeon cards. Below you can see how this actually works.
- CrossFire: The Refresher Course
- Advantages Of CrossFire Over SLI
- Image Rendering Modes
- Alternative Frame Rendering (AFR) Mode
- Xpress 200: The Nervous System Of CrossFire
- Catalyst: The Last Piece Of The Puzzle
- Benchmarks - What We Use And Why
- The Systems
- 3DMark 2003
- Doom 3
- Benchmark Conclusions
- Other Tests