FPS droppoff / stuttering in cruise or approx 30 minutes into flight

Sim Update 5 Beta | MSFS 2024 Virtual Reality
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ISSUE DESCRIPTION

Description of the issue: During a flight, usually around 30 minutes in and often during cruise, you can see the fps dropping or changing more than it should as you look around. It is the easiest part of the flight for performance. Looking on the FPS monitor there are lots of red line spikes.
If I come out of VR and go back in the problem goes away and everything is smooth again

FREQUENCY OF ISSUE

How often does this occur for you (Example: Just once, every time on sim load, intermittently)? Every flight

REPRODUCTION STEPS

Please list clear steps you took in order to help our test team reproduce the same issue:

  1. Start Flight normally

  2. Fly for around 30 minutes

YOUR SETTINGS

If the issue still occurs with no mods and add-ons, please continue to report your issue. If not, please move this post to the User Support Hub.

What VR headset and peripherals are you using: Pimax Super OLED, Pimax Play, Thrustmaster Boeing yoke, Honeycomb Bravo, Winwing FCU MCDU, Mobiflight overhead panel, IFR1

[PC Only] Are you using Developer Mode or have you made any changes to it? Only to view the FPS monitor when this happens

[PC Only] What GPU (Graphics Card) do you use? 5090

[PC Only] What other relevant PC specs can you share? 14900k, 64gb Ram

MEDIA

Please add a screenshot or video of the issue occurring.

2

Are you referring to something similar to this?

I’m experiencing it on every flight. It typically starts about 30 minutes in, lasts for a few minutes, then disappears—only to return again after 5–10 minutes, and so on. In the example above, it even occurred over open water, so it doesn’t seem related to heavy scenery loading. CPU or GPU overheating (aka thermal throttling) has been ruled out, HWiNFO shows <70 °C for the GPU and for all CPU cores.

For reference, my setup: RTX 5090, 9950X3D, 64 GB RAM, Somnium VR1. FPS is capped at 36 with a headroom of around 10–25 frames. The issue occurs regardless of whether I cap the frame rate or not.

I’ve tried just about everything, these are just a few examples:

  • With and without add-ons
  • Separating CPU tasks between MSFS and background processes (this machine is dedicated to only run MSFS anyway)
  • BIOS defaults vs. overclocking
  • Undervolting the CPU
  • Disabling Microsoft Defender
  • HAGS on and off
  • TLOD at 100 / 200 / 400
  • Terrain Pre-caching on Low and Ultra

Nothing seems to make a difference.

It feels like something intermittently overwhelms the MainThread or clogs the scheduler/render pipeline, but I can’t pinpoint the cause. I’ve seen 2D users report MainThread spikes as well, though I’m not sure if it’s the same underlying issue. In VR, however, the stutters are much more noticeable and disruptive.