X Server crashes

My X Server crashes or hangs about once a day. I’m using the NVidia X server because the Nouveau one crashes after about 10 minutes. I’m using Compiz as the window manager, but window stuff is not obviously going on when it crashes. Generic computer with i5 processor ran perfectly for 2 years uptime with Fedora 12 but then I decided to upgrade and Ubuntu 14 LTS was X Server stable but Compiz had issues with missing window content and now Mate 15 has this crash problem. Thinking maybe of going back to Fedora?

Compiz has been unstable for me in the past due to certain plug-ins, but not any more. Some Compiz plug-ins would cause the desktop to freeze up (then crash Compiz), but it didn’t crash the X Server entirely. In some very rare cases, I had to kill X.

Does the X Server crash when using Marco as the window manager?

Do you do anything specific that leads up to a crash? Such as playing a game, or using graphic accelerated programs? What model is the graphics card?

I have not used Marco for more than an hour and during that time the whole system wedged, but that was before I switched from nouveau. I may switch and see if the problem goes away, but I would prefer not to switch since I rely on some Compiz feature for my development (like transparent windows). If there is some way to debug this that would be better.

Before crashing this last time I was typing a tweet using Firefox. Before that I was editing some code using emacs in a Terminal. Nothing special or even close. The graphics card is GeForce 9500 GT.

Switched to Fedora 22 Mate and it runs much better, mostly due to Fedora. No more crashes so far and thats running the nouveau driver which never worked on Ubuntu. There remains one problem, the initial draw event (exposed?) from Compiz to the application is dropped sometimes. You can just resize or minimize the window and it draws correctly. Ubuntu had a similar issue but worse. Maybe someone knows a fix for this?