1. 
   Xgl
   Xgl was an X server architecture designed to take advantage of modern graphics cards via their OpenGL drivers, layered on top of OpenGL via glitz. It supported hardware acceleration of all X, OpenGL and XVideo applications and graphical effects by a compositing window manager such as Compiz or Bery...
   Found op http://en.wikipedia.org/wiki/Xgl
   
   

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