I have a recurring problem. Pimax Crystal, Pimax XR, OpenXR Toolkit. Lag in VR gets progressively worse during a flight. Day before yesterday I did several flights and all was fine. Yesterday I started a flight. Still, all was well and I was getting very decent framerates at takeoff. Activated AP, did some chores, 2 hours into the 2h 30 min flight I activated VR again. Now the framerate in the headset still said 30 fps, but the experienced fps was more like 15. Everything lagged. Got black edges if I moved my head fast, and no matter how slow I moved my head the image was choppy. Tried to restart the headset. Restart the Pimax Service. Physically turn off and on the headset. Change DLSS from Blanced to performance and back. Change from DLSS to OFF and then back. Nothing fixed the lag. Made it almost impossible to land, but I still landed as the flight was so long and there was so little time left. The lag was not visible on the mirror image on my monitor, and there was no lag on the when I exited VR and looked around the cockpit in 2D. Anyone else experience this and have a way to fix this during a session? My experience with VR in 2020 is that when doing “long” flights (anything more than 30 minutes) every subsequent flight is slightly worse fps-wise than the one before, promoting me to reboot my PC between long flights to be sure I get the best performance.
If you are using DX12 it is possible that after a while your VRAM is overflowing and paging to system RAM causing performance slowdowns. If so, try DX11 which is much better behaved memory management wise and is what I use for all my VR flying with no issues on very long flights.
I was using DX12, but got about 8-10 fps less, which brought it down to around 20 for the Fenix A320. This latest issue was while using DX11. But I did see stuttering like this in DX12 as well. The 12Gb on the 4070 Super might be to blame then.
Normally DX11 is pretty well behaved with VRAM use, so it shouldn’t be the 12GB VRAM limiting you then. I used to run 2020 with a 3080 10GB and while it came close to filling it in DX11, it never overflowed as far as I could tell. As such, it it probably something else with your setup and I don’t have any other suggestions at this time sorry.
Luckily I can’t say I’m having this issue. What hardware are you on?
Have you got the MSFS toolbar map opened while flying?, that some months ago degraded the performance overtime.
7950X3D, 32 Gb RAM, 4070 Super OC, Pimax Crystal. Running “the fps app that is not to be mentioned, even though it was mentioned by Asobo themselves on a dev stream”, FSLTL on very low setting (6 IFR aircraft, 0 VFR, 10 parked or something like that), Sky4Sim NG (but it was not open at the time) and SayIntentions Entourage. I believe that the flight that almost came to a halt was in the Fenix A320. But I have had these stutters in other aircraft as well but no this extreme. Usually if it is a short flight I will just reboot my PC and start over which eliminates them.