With a lower resolution set, I am able to enjoy all compiz fusion desktop effects on Ubuntu 10.10.
However, when I switch to my native resolution of 1920X1080, I am unable to consistently change backgrounds. Sometimes get 2 or 3 in a row, then wham, colored streaks across the screen or worse a freeze.
I am able to run 1920X1080 in fail-safe graphics mode. More importantly, all other compiz effects work, except the changing of the wallpaper.
HP Pavilion dx5150 small form factor, 2 GB RAM, AMD Athlon 64 X2 4400+, and the ever so horrid ATI xpress 200 GFX card!