I don’t know… one of my favorite references for UE4 VR perf has always been the Sun Temple demo. With OVR 0.4.2 i was able to run it in Direct Mode at locked 75fps with ScreenPercentage=140 (i have an R9 290 4GB). After 0.4.3 and the low-latency improvements i had to go down to something like SP=110 to keep the 75fps.
In my case i noticed that OVR 0.4.4 + UE4 4.7.3 seemed to have a nice perf boost compared to previous versions (had not tested it for a while) and was able to run it smoothly with SP=130 and ultra low-latency, a good compromise in my opinion.
Unfortunately 0.5.0.1 seems to have made it worse again, and i’m no longer able to run it with SP=130 without getting stuttering.