How Unity, Compiz, GNOME Shell & KWin Affect Performance

[Znurre]

Nice benchmark, and interesting numbers.
I am using KDE 4.6.3, with a GTX 460 and although I use compositing most of the time I have to turn it off even when playing games like gnujump in windowed mode since it causes horrible performance.
The problem is of course even worse in more demanding 3D games.

I take it the performance in your benchmark is due to using the (by default in most distros) "undirect windows" option and fullscreen benchmarks, which isn't much different from benchmarking the desktop without compositing.
It would be interesting to see compositing benchmarks in KDE without using this option, or running the benchmarks in windowed mode, and then comparing it to suspended compositing (Alt+Shift+F12).

[phoronix]

Phoronix: How Unity, Compiz, GNOME Shell & KWin Affect Performance

Those that follow my Twitter feed know that over the weekend I began running some benchmarks of the various open-source and closed-source graphics drivers. But it was not like the usual Phoronix benchmarks simply comparing the driver performance. Instead it was to see how each driver performed under the various desktops / window managers now being used by modern Linux installations. In this article are the first results of this testing of Unity with Compiz, the classic GNOME desktop with Metacity, the classic GNOME desktop with Compiz, the GNOME Shell with Mutter, and the KDE desktop with KWin. These configurations were tested with both the open and closed-source NVIDIA and ATI/AMD Linux drivers.

http://www.phoronix.com/vr.php?view=16073