I installed Slack 12.1 recently and I've been trying to decide which WM to use and such. I like XFCE and Openbox, and I'm leaning toward openbox for a simple base. I also tried out compiz swapped in for xfwm4 just to try out some of the effects. I want to try using openbox with xcompmgr for transparency, but it's really slow!

If I run glxgears in fluxbox or xfce plain, I get over 15000 fps.
...in xfce with compiz I get about 8000 fps.
...in fluxbox or xfce with xcompmgr I get between 700 and 1500 fps!
...in xfce with xfwm4's compositing enabled I get 700 to 1500 fps also.

Isn't xcompmgr supposed to be a very basic compositor? It should at least be faster than compiz, right?

I have an nvidia 7900gs running on the latest nvidia driver. My xorg.conf contains:

Section "Device"
Identifier "nVidia Driver"
Driver "nvidia"
Option "AddARGBVisuals" "true"
Option "AddARGBGLXVisuals" "true"
Option "NoLogo" "true"
Option "DisableGLXRootClipping" "true"
EndSection

does anyone know why xcompmgr might be this slow?

Perhaps this should be moved out of the Slack forum and into a more general software forum...