I have a Toshiba Satellite P775 with Optimus graphics -- I know Linus isn't thrilled with Nvidia over that. I don't know if that's related to my problem, however.

I'm running Ubuntu 12.04, with Compiz Config Settings Manager installed. At random intervals, sometimes just a few minutes, sometimes hours, the computer simply freezes. Everything stops, including the clock display. There's no response to any input.

I have to reboot by holding down the power key for about 5 seconds, and then I have to start my apps over again and redo whatever I lost during the freeze.

I have no idea how to troubleshoot something like this. Is there some kind of system log that will record the error?

I've looked over the forums and don't recall seeing any reports of this exact issue. Are there any graphics configurations that might be to blame?