http://bugs.winehq.org/show_bug.cgi?id=27467
--- Comment #6 from DL dredgingthelake@gmail.com 2011-06-13 07:39:56 CDT --- Just tested with nouveau and no tearing occurs (with GLXVblank = 1). So this must be a bug with the nvidia drivers. I'll file a bug with nvidia.
I also posted a patch that reverts the commit for those that don't wish to wait for this to be fixed.