Right now we've disabled Asynchronous Timewarp, because we also found it didn't work very well when the GPU was under load. I've actually gotten a "Synchronous Timewarp" (1:1 ratio to pull-up 30fps games to 60fps) to work almost perfectly, though some games require the user to tweak the timing a bit in the GUI... Not super user-friendly, but at least it works.
Anyway, this problem is just on normal games running at 75fps, with the rift also at 75fps. Wish I could see the source code for the display driver so I could find what the problem is...
