I have been experiencing a very jittery/unstable VR experience lately and looking for help to understand why and how to fix this issue. I cannot pinpoint exactly when this started happening but this is a first for me and I have been simming in VR since MSFS 2024 was launched without this present day issue.
On the ground the issue does not seem to present itself but as soon as I get airborne the issue becomes evident. I start off with a smooth and stable flight but as soon as I start moving my head the VR image becomes very jittery, erratic and unstable. It is so strange as it only happens specifically while moving my head around whether in the VC or in external view. If i donāt move my head around the VR experience stabilizes smoothly at 45 fps.
I am running latest SU2 with latest Nvidia driver.
Using DLSS swapper latest version.
HMD is Pimax Crystal Light with recently updated firmware and software.
Same experience when using the Pimax Crystal Light inside out tracking. Will fly for about 3 to 5 minutes and then gets very jittery. If I take the HMD off for a few seconds and then put it on, the issue stops only to start again in about 3 to 5 minutes. FWIW, if I use the Lighthouse tracking I do not encounter that problem. Iām not using SteamVR, only the PimaxVR runtime.
This same behavior occurs in other games as well.
It does not occur if I use my quest 3 with Virtual Desktop.
Leads me to believe it is either a firmware or Pimax Play problem.
So I reverted back to default DLSS version via the swapper tool and rolled back driver but still get jittery/unstable VR when moving my head around. It even happens when on the ground and I notice it when in the menu screen as well. I am using Pimax VR runtime. Gonna clear out my Community folder and continue testingā¦
Well thought Iād provide an update to my own topic.
Unfortunately the problem persists for me in VR. The best way to describe it is the image in VR āvibratesā when I move my head around up, down, left or right. I get a nice stable 45fps when i stay focused in one position but as soon as I move my head the sim becomes unplayable due to the vibrations of the image even though the fps is stabilized at around 45fps. Very annoying as I canāt figure out whatās causing this. Some things I tried -
Reinstall MSFS 2024 with clean Community Folder - no fix
HAGS off/on - no fix
Turned off FFR and Locked Target Frame Rate in Pimax Play (enabled them in the sim VR Graphics settings) - no fix
I am beginning to think it might be an issue with my Pimax Crystal Light headset but it seemed to work fine in MSFS 2020 so at a loss as to what is causing my current VR issues in MSFS 2024.
May not be the case but is there perhaps some kind of camera binding conflicting with VR ie VR is trying to have you look around but a camera binding is fighting you. Iāve never seen this happen on mine.
The reason for this is that Pimax Crystal Light offloads itās tracking entirely to the CPU and Pimax did something to the tracking algorithm from version 1.38 forward which made it very sensitive to CPU latency. This means jittery and/or laggy tracking when the CPU is also running other intensive, multi-threaded CPU processes like MSFS 2024. It didnāt affect MSFS 2020 as it was more single-thread focused while 2024 is more optimised to run across multiple threads and therefore interferes more with the Pimax tracking.
This only affects the standard inside-out tracking version of the Pimax Crystal Light as it has no onboard processing hence why it offloads the tracking to the CPU. If you have the lighthouse tracking faceplate that has some processing built-in and doesnāt offload as much or at all (not 100% sure) to the CPU. The affected versions are 1.38, 1.39 and 1.40 with 1.39 being the worst and 1.40 starting to get better again but still an issue. Pimax has said theyāre working on resolving it as a priority.
I dontā think its your HMD. My PCL does the EXACT same thing. Iām running the latest PiMax Play. I have a computer with way more than enough processing power and video power. The display still gets jittery just like you described. I can tell you from testing its not just something that happens in MSFS either.
I have a ticket open with them for this.
I have also gone to lighthouse tracking which works much better - but adds additional cost to the PCL. In my case I had to get 3 v2 lighthouses and a lighthouse compatible controler to have full functionality.
Iām still out of a lot of my depth in a lot of this for VR tuning - but my Quest 3 exhibits this whenever there is an issue with the bitrate - whether in Air Link or using the cable. Apparently the lag time in sending head tracking data back to the PC is just getting too great. If not using an automatic bitrate function, try lowering the target you may have set.
After 3 consecutive flights using 1.37 software I have not experienced the jittery head tracking issue. Thanks @ABF81 I will mark that as the solution to my issue. I hope Pimax can sort this out. I was thinking of upgrading to a Super but not sure about that at the moment.
FWIW, I worked with PiMax tech support for my jittering this last Sunday. End result was to put some clutter on the floor and put tape over the two top cameras. Once I did that I have not had any jitter. Iām still able to use controllers, stand, sit, etc. with no issues. Using the latest PiMax software.
Decided to update the Pimax Play software 1.40.4 and sure enough the jitters returned. Going to stay with 1.37 for know. Donāt know why this is affecting my system. Do i need to upgrade my CPU/GPU to use the latest software?
It doesnāt seem to be as simple as a CPU usage issue as it affects CPUs that should really be powerful enough. I suspect itās more a case of the tracking algorithm being super sensitive to latency and that shows up when youāve got an intensive, high priority, multi-threaded app (like MSFS 2024) running across all CPU cores. The tracking algorithm then has to āqueueā its commands behind that app and that causes the laggy/jittery tracking. This is just pure speculation on my part and based on nothing other than my personal observations and a (very) rudimentery knowlege of how CPUs function.
I would say you have much more than rudimentary knowledge of how CPUs function !
I have opened a support ticket with Pimax and here is a clip of the response I got from them:
please try updating to version 1.40.4 , as the versions between 1.39 and 1.40.4 did indeed have known issues with high CPU usage .
Did you try covering the top cameras on the headset like I posted above? Iām using the latest version of Play and that did take care of the issues. I havenāt had jitter since Iāve done that and I havenāt lost any functionality. Itās worth a try. I used painters tape over the top cameras. Based on your reports, I have downloaded 1.37 and will install that and remove the tape to see if there is a change.
And I do not belive its a CPU issue. Iāve watched my performance monitor when this occurs and I"m still only using 55% of the CPU with MSFS2024 and PiMax Play running.
And I set the PiMax services to ārealtimeā when I was still having jitter so if anything other programs should show pauses - but not PiMax. The PiMax services are back to default with the top cams covered now.
@Spirit539 Havenāt tried that yet but I guess I will give it a try.
Wouldnāt that interfere with the tracking ability of the headset by covering up the cameras?
From my experience - it has not. (Before I tried it at the suggestion of PiMax supoort I would have thought it woulnāt work.) I guess because it also has cameras on the bottom of the headset it does still work. I do have more objects on my floor than on my ceiling for the cameras to see and tract for orientation and maybe that is why it works better. PiMax seemed to think that was the reason.
