SlateUI ms dramatically increasing during VR Preview

I have a quick question about using the Oculus Rift DK2 with UE4.
I have run through most of the documentation out there, but was unable to find anything concrete regarding this matter.
I found that my fps drops significantly when looking at an area with multiple meshes painted via the foliage tool. My scene is really simple, its basically the first person template with the the projectile sphere mesh and the rounded first person cube mesh as the foliage meshes painted at a small concentrated location. While walking around this map in VR Preview, maybe 75% of the time I am achieving 75 fps. However the rest of the time my fps gets crippled to half of that around 37 fps. At these times I look through the GPU profiler, and the major difference I see is the SlateUI ms shooting way up around 16ms, which is much higher than 8ms while I get 75 fps. while playing without the VR preview as just first person, the SlateUI ms is very very low (around 2ms).
Now as I understand it, SlateUI has to do with HUD and stuff, but I have don’t have any hud in my game. Its just the template without the projectile gun and the cross-hair. I cannot understand the shooting up of the SlatUI ms. I bet my knowledge in this area is lacking and I have made some inaccurate assumptions of what is really happening.
If any one could shed light on this or tell me if there is something I am doing fundamentally wrong, I would really appreciate it.


Same issue.You have solved? Plz help.

Same issue. I did a quick test and found something weird. SlateUI costs much time even no UI elements in my game. Steps below:

  1. Create an empty project with a blank template.
  2. Launch the game from visual studio with ‘-game’ command
  3. ProfileGPU
    The results is bad, SlateUI costs more than 7ms !, my video card is monster (GTX 1080)

Have you found the source of this issue at all? Out of nowhere this problem has appeared in my VR project with about 15ms devoted to Slate (which I don’t use in the project). Was previously sitting at 90fps and suddenly this showed up >.<