.
I believe that the three 'Ripples' screensavers cause some 3d problems
which knock my LiveUSB Compiz off-line. This is a nuisance,
but easily reset with Knoppix>(Re-)start 3D.

The command 'less /var/log/Xorg*|grep -i graph'
indicates my that my laptop has Intel i810/GM45 chipset(s).

I'm disabling all three 'Ripples' screen-savers.