I closed program by program untilI found the culprit, it's baffling how the cause was Thunderbird but then again it does use a lot of memory and I have thousands of messages between dozens of mailboxes.
But still I don't think this should happen and Xorg shouldn't allow this either.
So for those who have mysteriously high CPUusage from Xorg start closing program by program until you find the culprit.
The interesting thing is that after reloading it, the Xor........