root@duocore2:/# nvidia-xconfig --add-argb-glx-visuals -d 24

Using X configuration file: "/etc/X11/xorg.conf".
Option "AddARGBGLXVisuals" "True" added to Screen "Default Screen".
Backed up file '/etc/X11/xorg.conf' as '/etc/X11/xorg.conf.backup'
New X configuration file written to '/etc/X11/xorg.conf'

root@duocore2:/#