Enabling vsync on my machine (R9 290X
@17.1.1, i7-4790K @ stock, 32GB RAM, Win10 v14393) absolutely obliterates performance down to sub-5-FPS levels. With it off the game runs as usual, circa 50 FPS in Ocean House 2 with no characters. Game is in 3840x2160 (native) "fantastic" quality, "fullscreen" mode (such that it is), all in-game settings at max except FXAA instead of temporal, and RT reflections off.
What other kinda info would be helpful? My monitor supports Freesync in theory, not that it ever seems to do much. Disabling it did not change the situation. I fiddled around with the settings a bit but it doesn't make much difference how they are set nor where the camera is. Vsync-ON = ~2-5 FPS. Enabling RT reflections initially gave me some crazy artifacting but it cleared up when I moved the camera.
Comments
http://forum.yiffalicious.com/discussion/488/how-to-get-help-with-issues
Maybe not always helpful. That one is from a run with the "novr" executable although running the main app directly produces identical behavior and an identical logfile save for an extra line about being unable to initialize OpenVR.
Updated to 17.1.2 driver; didn't change anything though.
Unity 5.6 is scheduled for release in March, and will have Vulkan support. I'm hoping this issue you're having will be fixed with that. Until then, I'm afraid you might have to leave Vsync off.
Sorry for the inconvenience.