Comment 12 for bug 813343

For all users that really need a running system:

Since I found out, that the Gnome3 (shell) environment is affected too (crashes), I temporarily installed xfce4 (compositor not enabled). All problems have gone. System is fast and stable. Nvidia-settings works like a charm.

I'll keep an eye on this until future updates will fix the issue. I am sure you guys will find a solution, unity is a really great software.