So I’m seeing this dramatic increase from +/-7ms to 50ms when playing a packaged project in Windows, but only when the preview window is in focus. As soon as I focus a random other window the problem goes away.
This happens with new 4.26 builds but also with much older builds that definitely didn’t have the problem before, so it’s either SteamVR, NVidia Driver, or Windows update… Has anyone else seen this issue? Any ideas on how to solve it?
There are a bunch of reports of something that makes the render thread block on GPU queries, and I’m guessing this might be another symptom of the same issue.
The comments in this thread suggest you might be able to mitigate the issue by turning on HZB occlusion or turning off occlusion queries altogether, although I don’t think the occlusion system is the root cause.
I’m experiencing similar issues with consistent shorter blocking regardless of the window state. It definitely doesn’t happen in older UE4 versions, so I’m guessing it’s some kind of incompatibility between certain version combinations of UE4, GPU drivers and SteamVR.