Arch Linux Kernel 3.10.3-1-ARCH
nvidia driver 319.32
If i change the accelleration from UXA to SNA the gnome-shell slows dramatically down. No error in the Xorg.0.log or dmesg log.
With the UXA accelleration everything works fine.
The obvious candidate is
Author: Chris Wilson <firstname.lastname@example.org>
Date: Thu Aug 1 14:49:36 2013 +0100
sna/dri: Disable TripleBuffering by default for compositors
which is more or less at the request of the gnome-shell authors.
(Except you didn't actually say this was a regression. And haven't even attached the Xorg log or stated the exact nature of the slowdown).
Created attachment 83719 [details]
The regression was the slow animation of the windows, when you change to the activity screen and choose workplace with another application.
The applications behavior is normal.
Option "TearFree" "true"
That's wip and definitely something you do not need whilst running gnome-shell.
*** This bug has been marked as a duplicate of bug 37686 ***