http://bugs.winehq.org/show_bug.cgi?id=31036
--- Comment #10 from Mykal Valentine zoku88@gmail.com 2012-06-30 13:24:38 CDT --- That's interesting since I don't see that problem at all (the slowdown, I mean.) Could be because of our different gfx cards.
You might want to file a new bug and put it under Regressions once you find which git commit makes you see the performance drop. Just for better bug tracking.