https://bugs.winehq.org/show_bug.cgi?id=39347
--- Comment #5 from Stefan Dösinger stefan@codeweavers.com --- Matteo claims he has seen this problem with ARB too. Not sure if it's really exclusive to GLSL.
We have at times seen problems due to GLSL compile times (Lip Sync in the Mass Effect 2 intro scene), I suspect something like this is going on here as well. If that was the case I'd expect Nvidia's shader cache and / or the command stream to improve things, but apparently that doesn't happen...