The real issue I'm having is that with all the old 2D graphics acceleration API's being deprecated in X11, you are stuck with Glamor to accelerate desktop compositing, and that only works if you have a later fixed function GPU, or a modern programmable GPU. If you're stuck with an old ATI FireGL like I am, X11 will vomit an error about the GPU not having enough instruction slots to do the job.

Its kind of baffling, the hardware is capable enough to run Half Life 2, but it can't composite a few windows? I'm almost tempted to go compile X11 myself and remove that particular check.