Sadly, you are not. I am having similar issues in 4.14.1.
What I’ve tried so far:
Stat UNIT reveals very bad GPU performance (> 100ms per frame)
Stat GPU reveals that almost all of this is in HZB, which I believe is related to occlusion culling.
I have upgraded and downgraded my NVidia driver, to no effect.
I have enabled precomputed visibility, added a precomputed visibility volume and rebuilt the lighting, to no effect.
The issue seems to be confined to VR Preview mode for me. Running the game from the VS debugger using -game <mapname> as parameters yields a reasonable frame rate.