http://bugs.winehq.org/show_bug.cgi?id=27959
--- Comment #8 from Stefan Dösinger stefandoesinger@gmx.at 2011-08-12 19:35:27 CDT --- Hi, Yeah, this is a total collapse of the framerate. Good catch on that Xinerama thing. Do you have direct rendering with Xinerama, or does the driver fall back to accelerated indirect rendering? This could explain some performance difference with buffer transfers. Does the problem also happen when you use Nvidia's twinview instead of Xinerama?
Either way I suspect there's a bug we hit in the driver. The best step would be to isolate this bug in a stand-alone opengl testcase that doesn't involve Wine and report it to Nvidia.