Ubuntu Unity Proves Very Slow To KDE, GNOME, Xfce, LXDE
KDE 4.9 with suspend effects on full-screen windows and GNOME Shell were by far the fastest desktops for the old OpenArena game. GNOME Classic, Xfce 4.10, and LXDE 0.5 were all much faster too than the default Unity.
With the newer OpenArena release, it's a similar story.
For World of Padman, it's a similar story with the default Unity desktop performance being horrible compared to other Linux desktops.