While I would agree that Oculus Runtime is far from being flawless, I’d recommend to do further testing to figure out which part of integration is at fault. Just switch to Extend mode and see if you still get low FPS or if FPS is back to 0.4.2.
Locking at 37.5 fps could be caused by several reasons. One of them - is Intel SpeedStep technology that incorrectly decides that CPU has nothing to do and lowers the frequency. I’d recommend to turn it off in BIOS and re-test. Another reason: the game is unable to achieve 75 fps (CPU bound) and leads to 37.5 fps (which is a way how SDK handles situation). I’d recommend to try to enable parallel rendering ( W knows how to do that) and see if changes anything.
We also have 0.4.4 + 4.6 (and 0.4.4 + 4.5.1) SDK integration available on github at https://github.com/Oculus-VR/UnrealEngine.
Even if you use UE 4.6 + 0.4.3 SDK, I’d recommend to install the latest 0.4.4 Runtime that contains newer and better video driver (yes, it will work with 0.4.3-based apps).
Answering to OP: I am unable to repro most of the issues, unfortunately. I’ve just synced to 4.6, re-installed 0.4.3 runtime and still don’t see these issues. I was able to repro the with the frame rate when ‘hmd mirror off’ is used, though. The bug report has been submitted.
P.S. I am not monitoring forum, so if there are any issues with Oculus integration it would be nice if someone pings me or post on Oculus forum: https://forums.oculus.com/viewforum.php?f=60