How Unity, Compiz, GNOME Shell & KWin Affect Performance

The "21" FPS frame-rate on the Urban Terror runs should be ignored as under GNOME Shell, this game outright failed to run properly except when using the NVIDIA proprietary driver. The proprietary AMD and NVIDIA drivers had respectively ran at the same speeds between the desktops, sans the broken GNOME Shell. With the R600g driver, GNOME 2.32 with Metacity was nearly twice as fast as KDE with compositing. With the Nouveau Gallium3D driver for the GeForce 9 hardware, KDE was slightly faster than GNOME2.