You’re not answering the question though… Maybe I’m not being clear.
What tool do you use to see your GPU utilization?
NVidia software, Windows taks manager, MSI Afterburner?
Windows taks manager is often displaying wrong info for MSFS (might not do that for other games, not sure, I never use it myself), NVidia and/or MSI afterburner should be correct.
Please provide your monitor resolution. I’m going to assume that you already have the sim on “ultra”. You now have to up the render scale or the game resolution. Depending on what your running now.
As Mort asked . What are you using to view utilitzation? Rivatuner, GPUz ?
4K monitor, I use rivatuner, gpi’z … Everything
I use rivatuner, GPUz*
MSI afterburner, GPUz and rivatuner…
I’m running out of ideas then. If you’re running on a 4K monitor, measuring the GPU usage with rivatuner, and with details at ultra, I would expect a 3080 to be completely maxed out (unless you’ve set render scaling to like 30%, which I don’t expect you did).
Only thing I can think of is the GPU throttling down due to temperature limits.
What’s the GPU temperature, what’s the airflow in the case like? Can you touch the GPU backplate without burning yourself after the sim has been running for half an hour? that sort of thing.
While we’re at it, check CPU temps as well. That might be throttling maybe?
If temperatures are under control, I don’t know what’s going on, unless you’ve limited FPS to a very low number with driver settings / vsync or something like that.
XMP profile for the RAM is enabled in the BIOS right? (just double checking, since I’m clutching at straws here). Ryzen loves fast RAM, and not using the XMP profile will default it back to 2133MHz.
the temperature does not go beyond 60°celsius … so I rule out that it’s a problem of overheating !!! it’s as if my gpu with mfsm can’t go beyond that power !!! I have done thousands of checks, both maximum energy settings by windows, and over clock gpu with msi afterbuner but nothing changes !!! I have XMP 2.0 active with rams at 3600mhz… I use an ssd gen 4, Using the dev mod of mfsm tells me " Limited by GPU "
Okay I found the problem… if the vertical synchronization is disabled, the gpu works at 100%… however without vsinc the images are not fluid !!! how should the screen be set to have a smoother imagine ?? I have an Oled 4K 120Hz monitor!
are you using vsync in the sim or nvidia control panel? what setting did you have vsync set to 30 60 fps?
what fps you now hitting does it exceed 120fps probably not but going beyond it would cause screen tearing.
Or do you mean the sim is stuttering?
If you set it to 30 fps the game is fluid … If I put 60 fps things change … It works between 40/55 fps but the experience is not fluid … But if I leave the 30 fps the gpu works at 60/70% but doing so I have more fluid experience … I have tried with GSync or Vsync of envy … But not Chía anything … I have tried hdmi 2.1 or 2.0 … same thing. … In the end I have a 120hz monitor that I have to use at 30 fps to have a better fluidity … Obviously all this happens only with flight simulator.
I think some people turn on max frame rate in nvidia control panel and set it to around the lowest fps you see when vsync is off then you don’t find the gpu usage going up and down. so set it to 40
But yeah any time you use a low vsync setting of 30 fps it’s going to under utilise the gpu cos it doesn’t have to render so much. With my pc have been able to find a setting where the gpu runs fairly steady. without using vsync.
To be fair if your settings are turned up and the sim runs well then leave it as it is. Things might change when DX12 is used in the sim due this summer I believe.
ah good, happy to see I’m not going mad 
well, it’s a matter of what’s important to you then.
If you enjoy the experience at the 30FPS (that’s what I have set myself as well), then yeh, the GPU will be running less hard and cooler.
If you really want to utilize the GPU more, with Rivatuner you can set a framerate cap at any FPS you want. If you find that uncapped it runs around 40-55 fps, then maybe limit it to 37. Should still be smooth, but the GPU will have more work to do.
Yes, but I still don’t understand why on MSFS, after 30 fps, I lose fluidity in the frames … I don’t understand! Patience I will remain with the doubt 
There have been a lot of topics about this already. Use the search function in the top right, and look for ‘microstutter’, you’ll find a few.
We’re hoping some of this will improve with patches, and especially the patch that comes along side the XBox release this summer. Apparently they’ve found quite a few optimizations while working on the XBox release, that will come to the PC as well.
In the mean time I would suggest trying not to focus on FPS/utilization too much. As long as your simming experience is enjoyable, just have fun in the Sim. The improvements will come eventually.
If you look at the core clocks and fps they usually aren’t stable in my case was able to find a combo of settings where this was stabilised which makes it fly a lot smoother. If it’s jumping around it wont seem smooth.
Odd thing in the sim sometimes my game is very stuttery when starting a flight, but if i pause it and move the render slider up, click apply and save then change it back the GPU and fps usually stabilise and the sim is a lot lot smoother.