After playing a few hours, FPS drops from 40 to 5FPS

What was the registry edit that you did to “fix it” ?

Please see:

The solution (solved) is located on the very first post

how can I do the CPU check to see if one of my cores if getting eaten up?

Task Manager. I forget which tab but it should be self-evident when you find it.

Looks like CPU 7 which is really 8 is completely maxed out?

Ah… that is probably the famous CPU LOD bottleneck. In short, your Terrain and Object Level of Detail settings as well as traffic settings (especially airplanes) might be just a bit too high.

LOD seems to be sent to the last CPU core, and if set too high, it tends to max out the CPU, especially at big airports. And if one core gets maxed out, the whole computer is throttled to keep all cores in sync with the slowest core.

When the GPU is the bottleneck, your FPS slows down. When the CPU becomes the bottleneck, you get immersion breaking stutters (and those are terrible).

You may want to check Dev Mode in sim, and follow the steps listed in this linked post and subsequent posts in the same thread.

This thread talks about maintaining a locked 30 FPS but if you have the system for it, you can maintain a locked 60 if you go for 15 ms instead of around 30 ms.

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But if you don’t even acknowledge that there could be an an issue, then you do not have to address it … (or even deny there is an issue)

Going forward, this may well get know to be “The Aerosoft Effect”, as they seem to have perfected this form of customer support.

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Performed the NDU registry change and still had FPS drop.

Next, I just removed the Toolbar Pushback after using it for the past several months. Performed a flight DTW-CMH. No FPS drop, using the FBW (latest exp) sitting at the gate after landing in CMH for 1hr. GPU still at 100%, same frames as when departing DTW.

Seems like the Toolbar Pushback jacks up the performance. THRILLED I can finally perform multiple leg flights


The basic design of Windows memory management has been the same for more than 20 years. It isn’t broken. Windows is designed to process many different types of programs from email to word processing to web browsing to games to watching video to video editing. Windows is designed to run these programs on many different hardware platforms. According to the MSFS FAQ, the minimum memory spec is 8 GB. I wouldn’t recommend this amount of memory to anyone. However, the design of Windows memory management allows MSFS to run with only 8 GB.

Windows is NOT designed to run only MSFS or even to run MSFS optimally. One “workaround” is to buy or build a PC specifically for MSFS…

As far as FPS decreasing or stuttering as memory utilization increases, this is because Windows moves parts of memory to the paging file virtual storage to accommodate programs needing memory to run. If any part of MSFS memory is moved to the paging file, FPS will drop or stuttering will happen because when MSFS needs that memory that is on the paging file, Windows has to retrieve it from the paging file and put it back into memory if there is room. If there is no memory available, Windows finds other memory to move out to the paging file to make room. All this takes time and even though it happens very fast, a few milliseconds delay is a stutter or a drop in FPS.

Windows memory management allows users to run MSFS, Navigraph, LittleNavMap, and a web browser to watch YouTube all at the same time.

When Windows starts moving memory around MSFS performance starts dropping. Personally, I watch my memory utilization and as soon as it gets to about 50%, I start looking for any unnecessary programs to stop.

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If this were an option that it should be possible to define what that is, and if that can be done then it should be possible to look at any system, and find what is missing to make it so that it is.

my mainthread is going through the roof over time.

starting with 50-60fps going all the way down to mid 20’s and low 30’s.

I run the sim at ultra preset 3840x1600
Sim is installed on an SSD, same happens with an empty community folder.

i7 10700k (stock)
32GB 3200mhz stock xmp profile.
3080ti not overclocked
Windows 10
1TB nvme (where the sim is installed on)

So after around 45 mins of flying from BHX and now West of Paris, which is notoriously heavy around CDG, im still getting solid fps. At the weekend over the same area i was getting around 20-25. All ive done is remove the latest better pushback mod from the community folder.

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Can confirm, landed back at BHX after 1.5hours of flight over france and back, the FPS is exactly the same as when i took of at EGBB in the same spot as when i landed with Better push back removed. I was using the FBW A32N mod. So for me it was the better push back mod thats caused all this issue. Hope this helps some of you.


I’m wondering if the memory leak has to do with the gate vehicles and animations in general. I removed Toolbar Pushback and that has helped - the sim was buttery all the way up to the gate. But when I called the tug and catering and baggage carts from the FBW flyPad, my FPS went down. Not nearly as badly as before, but still noticeable.

I am really thinking airport tasks like those you mentioned hit the CPU and lower FPS. Airports in general are really taxing on the CPU in MSFS whereas flight generally taxes the GPU.

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Check this post

Increase performances immediatly! AMAZING! Tested and aprouved! - Community / General Discussion - Microsoft Flight Simulator Forums

All traffic uses CPU, check to see if you are starting to mainthread limit at the gate with traffic. Turn some of the ground traffic settings (including airport workers, vehicle density) etc down, there to many of them IMO anyway. High LODs and traffic sliders eat CPU. I dialed most of my traffic densities back to 60 and road traffic back to 20. Still looks fine.

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I have disabled NDU as you suggested, because I do not want Windows wasting any CPU cycles keeping track of my internet data usage, but I can not speak to whether it has affected my performance in any way.

If I really wanted to test its effects I would probably need to make CapFrameX comparisons, flying the same route, with a clear rolling cache each time.

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I have also disabled NDU, but it did not fix issues with performance. I still had terrible stutters caused by Sim Update VIII and also massive performance degradation over time.


Are you mainthread limited though? If you are you need to optimise cpu/gpu load. Try reducing TLOD a bit. At least one other person saw a FPS pickup after a clean Fs install post SU8 too, but I’d check if youre mainthread limiting and reduce that first.