While not nearly as exciting as the AIGLX support, the fglrx 8.42.3 driver also contains a few improvements for the AMD Catalyst Control Center (AMDCCCLE). The 3D area of the control center (AMDCCCLE v1.5) has been reworked and now features improved anti-aliasing and anisotropic filtering controls as well as a vertical refresh control. When adjusting the AA and AF overrides, there is now a preview pane that shows a picture at that AA or AF level and a close-up view where any jaggies can be seen.
While this is a great improvement for the Catalyst Control Center, the anti-aliasing and anisotropic filtering can be improved. Presently the AA can be overridden only up to 8x while AF goes up to 16x. Now that the fglrx performance problems have been resolved, it would be really nice to see 16x AA support and ideally even their new adaptive or multi-sampling AA modes supported by their newer GPUs. This driver does introduce support for AA and AF on the R600 series.
From the "More Settings" page, the vertical refresh setting can be set to: always off, off - unless application specifies, on - unless application specifies, or always on. Now that the fglrx driver is on its new codebase and there are a few AMDCCCLE improvements already, don't be surprised if CATALYST AI makes its debut on Linux in the very near future for enhanced performance.