https://bugs.freedesktop.org/show_bug.cgi?id=60879
--- Comment #109 from Michel Dänzer michel@daenzer.net --- (In reply to madcatx from comment #107)
(Is there any reason why would the desktop animations feel much smoother and snappier than with the old hackofix?)
Sounds like the 'hackofix' disabled more SEs than necessary, so the card wasn't running as fast as it can.