So I play this game mainly in VR on my quest 3 using Virtual Desktop.
I use a dedicated Wifi 6e router, an a PC with an RTX 4080 Super and an AMD 5800x3d cpu with 64Gb of RAM. All my settings are perfecty tuned and when I start the game, performance are great and the experience is super smooth while using SSW.
But it very often comes a point when I start getting persistent stutters that won’t go away and my FPS stay around 4/5 fps bellow my half refresh rate. For instance if I set my headset refresh rate at 90Hz, the sim runs smooth at a constant 45fps with SWS generating the rest of the frames.
Then at some point, seemingly at random my FPS will drop to around 40/41FPS and will stay there. Sometimes after 10mn, sometimes after 2 hours… Even if I switch all settings to low, or even if I qui my flight and go back to the main menu my FPS won’t go back to 45… If I exit and restart FS2020 then everything goes back to normal. It just seems like the sim goes into a “corrupted state” that causes performance drop and there is nothing else I can do.
I tried to check all the obvious but didn’t notice anything. When this happen, neither my CPU not my GPU are particularly stressed or hot, my RAM or VRAM usage are also relatively low.
I have also tried to switch out and back into VR → it doesn’t fix anything
I tried closing and restarting Virtual Desktop without restarting MSFS → doesn’t fix anything either
I also tried different refresh rates on my headset and I have the same problem. With my headset at 72Hz it will be smooth at 36fps until it drops and stays bugged out around 31fps … Very strange
Anyone has an idea about what could be happening here ?
Grab the oculus tray tool, and on the fly, change the ASW settings. Try the different one’s = adaptive/Auto/45hz/45hz force enabled. It may be a bug with the ASW mode your using.
I am on the quest 3 too, and although ive experienced the odd stuttter after prolonged flight (45mins +) I haven’t had sudden drops like you describe.
I’m pretty sure the Oculus Tray Tool is only for the Oculus runtime when using Air Link or the Link Cable.
I’m using Virtual Desktop that uses SSW instead but it’s the same principle, just a different implementation of motion reprojection. I was indeed suspecting something like that due to how stable the fps seem to remain when it bugs out, around 5fps below the half refresh rate threshold. VD doesn’t have as many options for their SSW. It’s either always on, always off or auto. I’ve always used them. I always play with that settings “always on”. I guess I could try on auto and see if it makes a difference. I will also try to do some flights without any motion reprojection to see if I also notice the same kind of sudden and permanent performance degradation.
In the meantime are there there any settings either in the game or in the nvidia panel that are known to interfere with motion reprojection ?
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Sorry yes you are correct, i sim on link cable, because i found VDXR to be lower visual quality. So…Yes oculus tray tool wont be of use. Apologies.
I no of no Nvidia settings that interfere with Motion repro, sorry.
Funny actually, Ive just completed 2 flights myself tonight, and have noticed severe stutters on approach, and when i say approach, i mean like 10 mins from landing point. Its come out the blue, because a few days ago things were amazingly smooth. I am not sure if its related, but kind of sounds the same. My fps dropped too, and stayed there. Strange.
To be frank, ive never been able to sim on msfs consistently without some weird issue. Its very fidgety. I know its a highly complex sim and it is amazing, but it bugs the hell out of me, Its never consistent.
I’m hoping this may be a server issue. Sorry i couldn’t help, it now seems i am in the same boat as you.
Oh the irony!!
I am in oculus 3 via link cable and get the same Fps drop, random times, and doesn’t matter about location. This is not an Oculus issue more an Asobo issue.
Can play DCS, or Xplane and never have an issue in VR.
I am 10 seconds away from dropping MSFS completely and going 100% to XPlane.
Tired of spending most of my time fighting performance issues. I just want to fly.
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OK I did a lot of testing and I found a way to reliably and quickly reproduce the bug on my system. Here is what I do :
- I start the game fresh
- I launch a challenge/bush trip/lesson : everything is smooth during this first flight wether I fly for 30s or 30 minutes
- I restart the same challenge : I start getting the stutters about 15 seconds in …
With this information I was able to do a lot of test check settings one by one and see if I can find a way to avoid this very annoying bug. Spoiler alert : I still haven’t found any solution. Here is everything I have tried though :
- rolling cache on/off → the bug persists
- game in offline mode without streaming data → the bug persists
- DX11/DX12 → the bug persists
- motion reprojections on/off/auto → the bug persists
- a bunch of different codecs and bitrates (from H254 at 20Mb/s to AV1 at 200Mb/s) → the bug persists
- adaptive bitrate in Virtual Desktop on/off → the bug persists
So no luck so far. I still have some tests in mind to help me get in the right direction. I need to try with Air Link instead of virtual Desktop, and try different scenarios until I zero in on what exactly is causing this bug. I swear I’m gonna get to the bottom of this
any chance your CPU is getting hot and throttling down the clock rate?
No, my CPU is completely fine, somewhere between 60-65C when this happens. I actually upgraded my CPU a couple days ago but I had the same issue with the previous one.
Guys, i am going to save you loads and loads of trouble here. DONT start tweaking, messing and diagnosing. It is not your hardware nor software, its the game.
Nothing has changed on my PC. ive looked at all downloads, updates, driver updates this week, and non were made nor changed.
Only 2 days ago, the game was stunning. Just wait, it will come back.
While I agree that there is certainly something weird going on in the game, I still think it’s worth it troubleshooting it. Once you find the root cause of it there is often something you can do to mitigate it
I am 99.9% sure most of these inconsistencies are just down to the servers. There is nothing you can do except try another day (or XP12 lol)… 
It’s at the same time the most amazing software (game lol) ever, and the most infuriating.
I was about ready to throw the towel in after SU15 (with the supposed beautiful fixes) but my end was worse. After many months of tweaking SU14 and before, I had it sort of pretty good, then a step backwards.
Spent another couple of nights tweaking after my anger subsided, and it is kind of OK again now, but only “kind of”. So annoying. Shame I have spent a shameful amount of $ 
£ on extras or it would be easier to step away. But I still would not because I love it too much!
Yep, exactly this. VR is a pain! But worth it. I would say more than 50% of my time is testing and tuning. Not so fun!
Alright I’m a complete idiot. My issue doesn’t even have anything to do with VR. It’s just that I’ve been playing VR only since picked up the game again a couple weeks ago. After further testing I figured I should have started with the basics : I can reproduce the exact same performance drop (while repeating a landing challenge for instance) in PC mode with an empty community folder.
Alright last ditch effort : a complete reinstall of the game …
Update : I haven’t tried in VR yet but et least on PC mode the bug appears to be completely gone after a fresh reinstall of the game !
I tried flying again today, all starts out ok in VR, 40fps, then performace, just tanks, 8fps, for no apparent reason.
This is very frustrating and did not happen until SU15.
It looks like accumulating updates tend to “corrupt” the game. My game had been left untouched for close to a year before I got back in a couple weeks ago and had a bunch of late updates to do.
Now I will just do a fresh reinstall with every big update. It’s gonna save me a lot of trouble
I did a few flights in VR tonight. I can confirm that the game reinstall fixed the sudden performance drop isssue 
I had a super smooth experience the whole time at 90Hz with Virtual Desktop SSW (so rendering at 45fps in the sim).
If you experience weird performance drops and you have a decently fast internet, you should definitely try a fresh reinstall. Just make sure to backup your community folder and your UserCfg.opt if you don’t want to lose all your graphic settings.
Alternate Solution: while in VR mode, limit you FPS to 1 or so for a second and then uncap again. I use RTSS which comes with MSI Afterburner.
Seems to be some weird syncing issue which happens when you switch between VR and 2d back and forth several times like you do when changing stuff in VD or openXR toolkit.
There is also a very clear telltale when you have this happening to you: Monitor your GPU metrics, preferably with MSI Afterburner on a second screen. Have a look at GPU usage, GPU Power in Watts and FPS.
When the bug is happening your GPU usage will be at 99% while your GPU Power will be considerably lower than what it should be drawing at full load, which makes no sense at all. In my case ~150W instead of 200W for an RTX2070. Your FPS will also be tanking and the metrics will show a consistent Voltage Limit.
Now apply the fix I suggested and observe how your GPU Power goes back to full scale with normal FPS.
I noticed something similar in fs2024 when VRAM gets overloaded. I havent tried in VR or the framecap fix yet though.
give it a try if you suffer from this annoying bug
cheers