Per comment #9, you are forcing X or GDM to restart. Did you have something crash or freeze to cause you to do this?
@Lars Volker: When the cpu goes to 100%, does it drop back down? Does it stay at 100%? If it does stay up, you could run a backtrace using https://wiki.ubuntu.com/Backtrace#Already%20running%20programs after setting up the debug symbols.
Per comment #9, you are forcing X or GDM to restart. Did you have something crash or freeze to cause you to do this?
@Lars Volker: When the cpu goes to 100%, does it drop back down? Does it stay at 100%? If it does stay up, you could run a backtrace using https:/ /wiki.ubuntu. com/Backtrace# Already% 20running% 20programs after setting up the debug symbols.