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RaveTZ
Up and Coming
March 31, 2017

VR.WaitForGPU killing performance in Unity3D. Very difficult to profile other issues. Video Example

  • March 31, 2017
  • 13 replies
  • 14601 views
Here is a video showing what the issue is
https://youtu.be/n5ngEzZSKH0

I'm trying to release an update to Vanguard V but perforance has become a real issue.  The game runs at 150fps on my laptop but the framerate tanks when I touch the Oculus headset.  I get these nasty yellow spikes and the FPS tanks to the 50s, even on my desktop (980 GTX TI).  I then created a new scene with nothing but a camera and the default Directional Light.  The framerate goes into the 800s until I touch the headset.  It then tanks again to 90-100fps.  This is an empty scene.

Now, if this is by "design" it has made it very difficult to isolate any real issues in the profiler.  Any help would be great.

Unity 5.5.1f1 and observed in Unity 5.5.2 as well
Windows 10 x64




13 replies

Show previous replies
Spoon420
New Participant
May 21, 2019
I seem to be having a similar issue. No matter how empty a scene is, I can't seem to get more than 60fps almost like it is syncing with my monitor, instead of my headset. This Thread was 2 years ago.
pawbab
New Participant
August 22, 2023

I know this is quite an old thread, but in case anyone was looking for a solution that I stumbled upon, this is:

Specification: Unity 2022.3 LTS
Pipelines: URP
Build settings: PC, SteamVR

When the problem occurred: After turning on the second camera (even on an empty stage)

What caused the performance drop: added Screen Space Ambient Occlusion in RendererFeatures.

Solution:
I duplicated AssetRenderer and disabled Screen Space Ambient Occlusion for it. In the Render Pipeline Asset, I added a duplicate AssetRenderer to the RendererList. In the second camera, in the Rendering section, I set the Renderer to the duplicate one. This allowed the first camera to have Screen Space Ambient Occlusion and the second not.

This solved my problem. I hope I could help someone (even myself from the future if I forgot :D)

    mightychili
    New Participant
    September 19, 2023

    Came here with a different, but related issue, where the HoloLens 2 build with MRTK 2.8.3 was showing very low FPS due to FrameEvents.xrBeginFrame and WaitForGPU. Removing an unused camera from the scene, similarly to what pawbab suggested solved the issue.

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