I'm currenty trying to enable 3d desktop effects on Ubuntu 9.10, on dual screens with compiz-fusion, however I'm using dual screens, and I think that may be the problem. It says "composite extension not available." I'm using xinerama with a screen resolution of 1280x1024 for both monitors. I have an NVIDIA GeForce 8600GT graphics card. I'm thinking xinerama only allows 3d acceleration on one screen? Any one out there know a way around this? Here's my Xorg file.