Poor Performance with RTX 3080 and 3900X CPU " Limited by MainThread"

Dont mind my run ons, I am not content. I am no longer satisfied . Cant believe this, and I am not playing with my settings, lasso or anything, this Simulator should run like it did prior today , at 12:52 am EST, I just closed out the simulator and said well, let me jump on this forum and check out if I am alone. Like I said , am dissapointed, and feeling well out of sorts. Please read. …
I also sent this same message to micro-soft development team. Word for Word copied message,

FPS, running at same refresh rate of my monitor , with locked vertical sync. I never set my refresh rate higher , although my monitor max rate is 144. I always locked it at 60 . Now with the newer updates, I have to turn off vertical sync, set my monitors to run at 144 to fly even the smallest of aircraft, to at least hit 35 fps.

This is not right. My system spec’s are well beyond the average, running a 3080 Nvidia card, process is a 3950 on a Formula VIII mb. , both the processor and video card are water cooled by HYDROLUX including has two built in radiators, and temps never reach above 50, running this flight simulator. I was hitting 60 FPS on ULTRA prior to the update. Ohj my drives are well well suited for many types of programs. Believe me. I am not putting my spec’s on line but you get the point. I can do better if I had a 4K monitor, since my card demands that anyway in the 1080 max that I have may slow it down a little, but like I said prior the updates the were available , It took my fun time down to a punishment like experience. I wasnt upset about the icing up on the wings, I said ms and its affiliates will fix that, but I am not happy for sure with the FPS and it using less of what my card can offer. i tried different FPS counters and they including the flight sims developer FPS show the same results, plus what the sim is not taking advantage of.

When they first advertised the release of the simulator, I ordered it way in advanced to it being released. However, I was sooo busy during the summer, I didnt have a chance to actually access the Microsoft Store to download it. I finally downloaded what I already paid for and believed was a good product to invest in and when I had the chance to download it. Then later run the package, it was fantastic, minus the over kill in ice build up. I was flying real weather in time. Buy I thought that was amazing anyway. Ice buildup, wow great compared to years ago. I did watch it melt away after I landed blind. I sat after I parked that baby, looked around in the ■■■■ pit and said wow what a change since FS9 and prior. So some time later after I turned off my PC, I mean days later, I had a moment to fly again, but guess what UPDATES. I was well no problem. I accepted the downloads, in my content manager . Flew a litte and noticed well bad hipcups. Basically horrible FPS, I did everything to see why. I later learned that I wasnt the only one, but more since I put time into trying to figure out the issue, I also noticed that the simulator unlike other softwares doesnt take advantage of the video cards such as mine and I am sure others who fly this simulator too.

Why, I am preminum here alone in the world, regardless of what others may think. I believe in my self and nothing to prove. I dont ask for much , but i think the developers regardless if you are affiliated with others building this simulator should focus on not only providing better experience over large airports in particular areas of the world, but should fix the issue with the MSFS 2021 not utilizing a video cards potential, alsop The united states such as Pennsylvania and other states having same issues as in other parts of the world. You focused alot on Europe , hmmm? But anyway the icing too, but the the software not using my card’s full potential including those that have 3090’s is bad. Not good. I am a patient person but not that patient. WELL anymore especially when I found out the update I download tonight on 3-26-2021 was not what should had been. It should address the video card potential issue. Please reply.,

I am sorry none of this worked for you, but denigrating somebody for trying to be helpful is not appropriate and discourages people from being helpful in the future. Please understand:

1.) I made no claims as to whether or not any of this would work for you.

2.) I took time out of my busy day to put this together in hopes that it might help somebody. I was sharing my experience and what worked for me.

We’re all here to enjoy FS2020 and help each other have the best experience possible. Please be more respectful of the community.


Please keep the conversation in this thread related to the topic.

Do not fight back and forth with each other. For some people the sim works fine, for others not. Same with “fixes” and “solutions” that people offer. You’re not alone and things are being worked out to create the best possible experience for every one.

Of course, frustration is inevitable if things don’t work as expected. But try to respect each other.

Thanks :+1:


Myself I have a
10900K @ 4.9ghz
,RTX 3080,
32 GB Ram 3600Mhz
and at a airport like CYOW default I only get 32 FPS with any plane with settings between ultra and high,even If get my settings down to High the frames don’t even change.
Not to impressed,I’m getting the same frames like when I had a GTX 1070 and a i7700k,no improvement whatsoever.

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I have tried everything under the sun. Literally spent hours trying to figure this out.
I did a complete reinstall and nothing changed…

Ultimately the question would be if MS is still working on this…?

Excellent question!
Though I think they are working on it, (albeit not hard enough)
MSFS is now a bit better FPS-wise than it used to be, at least it holds 30 FPS with my rig…

See also if interested:


Still also have the problem that only one core (the last one) is always at 100%. It is also always the last one. Never an other core…

Any solution yet for this problem?

Specs. 10900k
64mb 3600mz
Asus 3090 OC
Game mode on
Hags on.

Changing the game mode and hags does not solve this.

The only real solution to that will be DX12

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Well the degrading over time in high detail areas makes complete sense because of the LOD levels of the buildings and objects. When starting in an area, the lowest resolution graphics and object detail is most likely loaded but as you cover more and more area, the more detailed LODs will get loaded and persist putting much more of a graphical load on your system. The loading and converting of that high resolution photogrammetry data in my mind is the number one source of slow downs and stutters.

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I have it not only in high detail areas but also in the Australian desert. It goes down from 45fps in the beginning and some hours later it’s only 5fps. There is nothing to load in, it was all grainy sattelite photos, flat terrain and small amount of trees over there. And memory usage was not that crazy either (5-10GB).

You are not alone. Same situation with my RTX3090. Long noisy silence from ASOBO who does not communicate on the subject. Certainly DirectX12 could provide a solution for the multicore management of CPUs. But there is a fact that I do not understand, why (even on directx 11) the simulator worked better before the last updates ?

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DX12 helps in GPU limited games, less layers of abstraction and more efficient use of the GPU. For the most part, MSFS is not GPU limited. It will definitely gain some FPS at 1440p/4k for most people, but it’s not going to be the performance revolution MSFS needs.

The frame drops, stutters, those 5-10 second hangs that happen, that’s CPU. They have got to get more things off the main thread and things that have to remain on the main thread hot path as efficient as possible.
A win was moving the terrain streaming off the main thread.
However, I would bet the instruments (especially glass cockpit) are running on the main thread OR doing a blocking sync with the main thread. Stuff like this needs to leverage the parallelism of modern CPUs.

It’s hard work and can be a real challenge depending on the game engine design.

DLSS 2 is what we need, once DX12 is sorted out


users have the hope that DX12 help:

[ 1 CPU Core in 100% ] and [ GPU in Less than 100%, e.g 60% ]

  • exception is: the 100% one core load is the DX11 render thread
  • assumption: DX12 fix that

[ load for each core is far less than 100% ] and [ GPU is in 100% load ]

  • your GPU is already in full load and will not be faster with DX12

You can test how much a performance boost DLSS would give you, lower your resolution in game (or resolution scale). That’s what DLSS does, lowers the render resolution then upscales the rendered image back to your target resolution. It works great on GPU bound games to not waste the GPU perf budget on pixel count.

While you will gain some FPS (mostly at 4k), you likely won’t get anywhere near what you were expecting. That’s because MSFS is CPU bound, not GPU bound.


Will check that out in war thunder, as that game does make use of DLSS 2.0, will let you know the difference in fps :+1:

Things like DLSS will only do something for people with a very fast CPU and an old GPU.

Virtually everyone is CPU limited.

What if you have a powerful CPU paired with an underpowered GPU? Does that include being CPU limited too? :eyes:

No, but that’s rare I think. People tend to upgrade the GPU only because they think that’s more important (which is true for most other games), and because a cpu upgrade is more expensive when they have to buy a new motherboard too. Then they find out their FPS didn’t improve at all.

10700K here and a 2060super and I am extremely GPU bound during flight its around 17% 100% GPU but overall the sim is very smooth.Only kept my GPU because of the shortages.Maybe when I get my hands on one of those shiny 30series it may change.