ATI Feature For Textured XRendering
 

Earlier this week we published benchmarks of the XRender
extension using NVIDIA's latest beta Linux driver, which had a
substantial performance boost thanks to Render improvements with this
latest driver. One of the questions that have since come up is how
ATI/AMD's binary Linux driver compares when using this X extension.
Well, right now, it lags behind NVIDIA, but a Phoronix Forums member has
discovered a hidden ATI Linux option that should yield XRender
performance gains.

http://www.phoronix.com/vr.php?view=11528