Constant heavy stuttering in VR with SteamVR

I used to have acceptable performance in VR, but since yesterday I'm experiencing constant heavy stutters roughly 6 times per second, matching the pattern seen in the attached graphs.
The stutters and graph patterns also appear while in the menu and even in the content updater screen.
This started happening yesterday after I briefly switched to OpenXR/OpenComposite via manually openvr_api.dll replacement (which had worse performance, also see this comment) and back. This could be coincidental given that SteamVR 2.1 also was released yesterday.

Performance in OpenXR is okay-ish with occasional drops which is weird in its own way - but I'd like to go back to original SteamVR performance.

Hardware

• Varjo Aero
• AMD Ryzen 5900x
• RTX 4090

Software

• Varjo Base 3.10.3.25 (recent), running the HMD on 39ppd
• nVidia GeForce driver 546.17 (recent) or 537.58
• Windows 10
• rFactor 2 public release
• Graphics settings: "ultra" or "very low"

What I tried so far (without success)

• Re-installing rFactor 2 and all content
• Switching nVidia drivers (see above)
• Trying SteamVR public, beta, and temp_v1.27.5 branches
• Using min graphics settings
• Comparison: Assetto Corsa runs perfect on either SteamVR or OpenXR

I really enjoyed rFactor 2 until this issue occurred and I'd be very thankful about any hint, even if it just concerns how to generate debug data.



Solution
I was not able to resolve the issue with SteamVR, so I focussed on improving performance in OpenXR/OpenComposite:
In my particular case, the issue has been that I limited the framerate to my HMD's maximum framerate (90) via the setting in the OpenXR in-game overlay. This had resulted in random (wrongful) throttling of the framerate from 90 down to ~80. Setting the limit to Off solved the issue.

 

From outside it looks like some kind of priority issue. At some point some other application "locks" the CPU due to prior use and then there is a compensation of Steam VR to compensate the loss ...
And the cyclicity is weird.
Check in task manager if some other application causes those spikes ...

 

Latest Windows Update is giving lots of issues, I would try to revert the latest one from recovery mode and disable all updates.

 

One major thing in Windows is to try to set services to manual if possible, and remove any applications that starts and is not used, like Rgb softwares, overclock apps, gadgets, widgets, ...
Less is more on Windows systems.

 

@atomed Uninstalling all Windows updates to a state from last week (when everything worked) did not fix the issue unfortunately.
@DanRZ In Task Manager, I can't see anything suspicious concerning neither CPU nor GPU. Also the spikes are not visible in the graphs in Task Manager. Would you know a tool that allows for capturing the processes using CPU/GPU at a given time?

 

I also have issues with VR since a few days. But only in rF2. Other games like ACC run like always. The frametimes nearly tripled.

For me i could track down the issue to the use of fpsVR. When i completly disable it i nearly have zero issues anymore. When i use an older version of fpsVR via the betas i still have issues but they occure a lot less.

 

Steam vr is an enemy, the second thing with a 4090 is not to lower details, is to lower resolution.

 

Since there doesn't seem to be a solution via SteamVR, I'll try to resolve the occasional slowdowns when using OpenXR instead.
These now also occur in AMS2 (which hasn't received an update in months and used to work perfectly), with the same pattern regardless of graphics settings: 90 FPS, but annoying drops to 80 FPS (according to OpenXR FPS overlay). AC works perfectly using the same OpenComposite version.
Thanks for all the advice so far; I'll let you know if I found a solution (or ended up re-installing Windows once again).

 

There has been a lot of discussion on something like this from another Aero user in the rF2 Discord (https://discord.com/invite/rfactor2) VR channel. I would suggest you try there. I don't think it has been solved, but at least you can eliminate some things.

 

I found a solution to the slowdowns I observed when using OpenXR; see last section of original post above.

 

Today I fired up rf2 with Quest 3 and suddenly it was unplayable . 9 fps lol
4090/i9-13900k here.
3 days ago it was perfect and very smooth. SS-150%…. 90fps.
I didn’t update windows( manual update here). I tried everything but nothing .9fps and stuttering.
I had the idea suddenly to close fpsvr app and the stuttering gone and it’s 90fps again.
Strange thing that fpsvr has never caused me any issues.

 

Ah great that i am not the only one with this issue. I thought i am going crazy

 

The strange thing is that 2 days ago I had ZERO. Issues with FPSVR/rfactor 2….

 

Yep me too. But there was an Update of fpsVR on 20.11.2023.

 

i could track down the issue a little bit more. It‘s not 100% related to fpsVR. I also get this performance issue occasionaly even if i don‘t have fpsVR enabled. Can you also confirm this?

 

I will check tomorrow and update here . However rfactor 2 sucks with vr. Studio397 hasn’t worked on rf2 vr performance in the last 2 years.

 

Pretty interesting solution - I am not using the toolkit at the moment, but was testing opencomposite and pimaxxr today; when I entered the track I had massive stutter and kind of jitter, no matter if I was using base stations (lighthouse) tracking or using the axis based function of the Pimax headset.

I found switching off Windows graphics scheduling as mentioned here https://www.reddit.com/r/Pimax/comm...=web3xcss&utm_term=1&utm_content=share_button to be the solution.

edit: fpsVR causes -5 FPS with my setup and also using HUD ingame costs a couple of FPS

 

There are other applications running a lot better, yes - there were some improvements on the track surface depiction where people (like me) had the effect (using a Rift S or a G2 e.g.) of too bright track surfaces ... if there will ever be upgrades / improvements in VR performance - I have doubts.

 

Ok i maybe found the root of the issue. Do you start rF2 over Steam or do you start it via a desktop shortcut with parameters?

I always started it via a desktop shortcut with these parameters "D:\Steam\steam.exe -applaunch 365960 +VR". And this seems to be the problem. If i start rF2 directly via Steam i have no issues using fpsVR. But if i start rF2 via my desktop shortcut i immediately drop from 1ms frametime in the main menu to 30ms if fpsVR is enabled

 

I start it from Simxperience software Simcommander.