* SuperTiling: CrossFire's standard dual-GPU rendering mode. It divides the screen up like a checkerboard, allocating adjacent squares ('quads') to alternate GPUs. (To continue the checkerboard analogy, one card would render the white squares, and the other the black). SuperTiling supports all Direct3D applications (but not OpenGL). However, it provides the least performance enhancement of the four modes, a rough estimate being 1.15 times the power of a single equivalent GPU. This is due to the fact that SuperTiling does not allow the geometry of a scene to be scaled between two cards. It is worth noting that SuperTiling only works on cards that have an even number of pixel quads so a setup with an X800 with 12 pixel pipelines paired with an X800 master card will not be able to render the SuperTiling mode.
* Scissor: Divides the screen into two rectangles, one above the other. This is the default operating mode for OpenGL-based applications. Unfortunately, the performance boost with Scissor mode is approximately equal to the SuperTiling mode. This render mode is more commonly known as Split Frame Rendering (SFR), which is how nVidia refers to it in SLI. In theory, SuperTiling should provide higher performance, because there is a better chance the work will be evenly divided between the two cards. Using Scissor mode means that the system has to carefully choose the "cutting point" in order to balance the load.
* Alternate Frame Rendering: The fastest mode, Alternate Frame Rendering (as the name suggests) sets one GPU to render odd frames, and one the even frames. While this produces a high performance boost, it is incompatible with games using render-to-texture functions because one card doesn't have direct access to the texture buffer of the other. Like nVidia, ATI uses game profiles for Alternate Frame Rendering, but nVidia allow you to create profiles to use AFR on any application.
* CrossFire Super AA: This mode is not designed for a large increase in frames per second; rather, it is intended to improve the quality of the frames rendered (hence 'Super AA' - super anti-aliasing). Super AA is able to double the anti-aliasing factor (eg. 4x, 8x and 12x) without any drop in framerate.
