UE5.4 VR Scene Crashes in Headset After Huge FPS Drop (Nanite Enabled, No Light Baking)

Development Programming & Scripting
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Hey everyone,

I’ve hit a major wall with my UE5 VR project and would really appreciate some help or guidance from anyone who has experience optimizing for VR in Unreal Engine 5.4

Project Setup:

  • Unreal Engine 5.4
    -Meta Quest 2
  • Started with the Third-Person Template
  • Built an extensive scene including:
    -A large open field with a river and procedurally generated village
  • Later, I added the VR Template via the Add Feature or Content Pack option in the Content Browser
  • Using Nanite for everything I can
  • No light baking yet — all lighting is currently dynamic
  • Target platform: PC VR

My Hardware:

RTX 3080
Ryzen 9 5900X
64GB RAM

My Performance Situation:

  • In the editor viewport, the scene runs at 60–90 FPS after a lot of optimization (LOD setup, Nanite, culling, and other methods)
  • As soon as I enter VR mode with the headset, FPS plummets to 10–20, even when standing still
  • After a short time, the VR session crashes entirely (the editor doesn’t crash, just the VR runtime becomes unstable)

Things I’ve Tried:

  • Tried enabling Forward Shading and Instanced Stereo Rendering - When I do this, my level crashes on load — I can’t even enter the scene afterward without reverting the file
  • It seems like enabling either of these breaks the level or causes engine instability

What I Desperately Need Help With:

  • Why does performance drop so drastically when switching from the editor viewport to VR?
  • Why does enabling Forward Shading or Instanced Stereo Rendering cause the entire level to crash?
  • Are there known issues with migrating the VR template into a Third-Person Template project
  • Could there be **conflicts between the VR Pawn and Lumen ighting
  • Should I consider switching some lighting to baked, or does Nanite + dynamic lighting + VR simply not scale well without Forward Shading?

My goal is to get this scene stable and performant enough to walk through in VR without constant crashes. I’m open to downgrading visual fidelity, but I don’t know what’s causing the crashes or if the rendering path is incompatible with my scene setup.

Thanks in advance for any tips — I’m stuck and would really appreciate insight from someone who’s navigated this before.