Installation of AIGLX
Add the following options to the corresponding sections in the file /etc/X11/xorg.conf:
 Section "ServerLayout"
         Option "AIGLX" "true"
 EndSection
 
 Section "Extensions"
         Option "Composite" "enable"
 EndSection
 
 Section "Device"
         Option "XAANoOffscreenPixmaps" "true"
 EndSection
Nvidia user may also need:
 Section "Device"
         Option "AllowGLXWithComposite" "true"
 EndSection
 
 Section "Screen"
         Option "AddARGBGLXVisuals" "True"
 EndSection
 
 Section "Module"
         #Load "dri"
         #Load "GLcore"
 EndSection
Activation for KDE / Xfce4
http://www.mail-archive.com/debian-user-french@lists.debian.org/msg130812.html
First edit the file /etc/xdg/xfce4-session/xfce4-session.rc and comment the lines regarding xfwm4 :
- Client0_Command=xfwm4
 - Client0_PerScreen=False
 
Secondly, you must create a file ~/.config/autostart/compiz.desktop taking care of compiz start :
Desktop Entry Name=No name Encoding=UTF-8 Version=1.0 Exec=compiz --replace --fast-filter --use-cow X-GNOME-Autostart-enabled=true