Comment 7 for bug 1387558

With 14.10 it was almost like You said.

Full description:
1. power computer on - cold boot
2. log in, open programs, do work, etc.
3. connect second display (rotation is preset as "Counterclockwise", work for say 4 hours with both displays
4. remove external display (until this moment all was smooth)
5. observe choppy performance on laptop display
6. reattach the display - all is smooth again
7. suspend, go home, unsuspend, observe the same sluggishness with laptop display
8. suspend, go sleep :)
9. go to work, unsuspend, observe sluggishness
10. connect external monitor - all is smooth again
11. change rotation to "Normal" instead of "Counterclockwise" - sluggishness is back
12. change rotation to "Counterclockwise" - all is smooth again

The thing is tho, that I'm not able to work with such sluggishness so I removed 14.10 and reinstalled 14.04, so I will not be able to verify any patch or suggestion or anything.
So, if noone else is affected, this can be closed.