At the recent European X.Org Developers Meeting KDE developer and Trolltech employee Zack Rusin presented a new acceleration architecture named Exa (eyecandy X architecture) for X.org. Being based on KAA (KDrive acceleration architecture) it's designed to be an alternative to the currently used XAA (XFree86 acceleration architecture) with better acceleration of XRender which is used by composite managers for desktop eyecandy effects. The next X.org release which is expected to contain Exa is planned to be released in September.
Making existing graphic card drivers using XAA take advantage of Exa is said to be easy and Zack volunteered to, besides bringing Exa into X.org, to port all unmaintained graphic card drivers as soon as he gets the respective hardware in his hands. Exa is meant to improve the desktop experience and bring users some much needed eye-candy while Xgl, an X-Server layered on top of OpenGL is being worked on.
Source  with live links.