I know there are similar questions about VR performance but this one is specifically related to vsync. The worst case for vsync should be halving your framerate correct? I am, and several others I have been working with are seeing this happen. When we enable vsync we get the 37.5fps issues despite frames being well over 90fps with it off. The fps has to get very high to not drop to 37.5fps.
NOTE: I had another issues that was related to vsync and a piece of software I had. this is a different machine and different OS.
for those running an nVidia card, go to your drivers settings and put the v-sync in adaptative mode (not half). At least, while this issue is not resolved, you may get a better experience.
Also this seems to be tied to specific materials behaving worse in VR. If you remove them from view it acts as expected and vsync only has a worst case 50% performance hit. Can someone please help? this doesn’t make sense
Have you noticed a pattern to the materials that are causing the slow down?
I’ve also been fighting with VSYNC issues in 4.6 (I’m using OculusVR’s 4.6, which compiles against the 0.4.4 SDK). Without VSYNC I can get over 90 fps in my game’s level, but then I turn on VSYNC and it can plummet to 37.5 fps. Through profiling, it seems that my present time greatly increases with VSYNC on, which sounds like the GPU is idling while waiting for the chance to present the current frame. Everything ran fine in UE4 4.5.1 and OVR runtime 0.4.2 (same GPU drivers between these runs).
For one of my levels, I’ve found that UE4 is the culprit with its HZB Occlusion in 4.6. Calling “r.HZBOcclusion 0” in my level blueprint helped in this case. Maybe that will help with your material issue?