Alternate Frame Rendering (Afr) Mode - ATI Technologies X1900 - Radeon XTX 512 MB PCIE Video Card User Manual

108 CrossFire™ Rendering Modes
Although Scissor Mode is generally a less efficient means of splitting the
workload than using SuperTiling, there are a few cases where it can be
more efficient. It is supported by CrossFire™ in order to maximize
compatibility and performance.

Alternate Frame Rendering (AFR) Mode

In this mode, all even frames are rendered on one GPU, while all odd
frames are rendered on the other. The completed frames from both GPUs
are sent to the Compositing Engine on the CrossFire™ Edition card, which
then sends them on to the display. By allowing both GPUs to work
independently, AFR provides the greatest potential performance
improvements of all the available modes. It is also the only mode that
allows the full vertex processing performance of both GPUs to be
combined.
1 PCI Express® Slave Graphics Card
2 Radeon® X1900 Series Master Graphics Card
3 Partial Frame Rendered on PCI Express® Slave Graphics Card
4 Partial Frame Rendered on PCI Express® Master Graphics Card
5 Final Rendered Frame on Display