This is the application gtkperf running through ebrainpool. Its a good way to understand where the display (Xorg) fits into this mix. Here the app is actually running my machine (supernova) which has the Intel x3100 graphics card and is being also run simultaneously from my machine, through ebrainpool on a machine with an ATI radeon. The pics below are shots taken out which show the results (yeah we know, bad video... sorry about that)
Notice in particular the times taken, rather the difference between the two. Keep in mind here this is the Same application, running of ONE machine, the same machine. It is installed on mine (intel x3100 graphics - 29 seconds) and the other machine running this very same installation of gtkperf of my machine, but via X, rendering it on another machine (ATI radeon graphics - 16 seconds). The Cpu being used in both cases is really mine, the graphics cards is the only difference.