Reducing MSFS **CPU** load (Limited by CPU)

Thanks. Interesting, since I was flying the JF Warrior with the GTN750 for the tests. But even while AAU2 is mostly dealing with the glass cockpits, it seems to be making trouble with the rest too.

However, I always had those hitches/freezes since the beginning, especially while turning. In straight flight it’s far less pronounced, so I ask myself whether it has anything to do with streaming. After all while turning the sim probably might have to stream more data than during level flight since the scenery is changing far more rapidly.

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Greetings -

I totally second your opinion and experience, hitches / stutters that happen while turning and are related to streaming, because in a turn the sim has to stream more data than during level flight since the scenery is changing far more rapidly.

If you are flying over a photogrammetry scenery area, there is much more data to be streamed that on a purely autogenerated scenery area hence in this situation the hitches / stutters are worsened.

The use of “Off Screen Terrain Pre-Caching” helps to reduces stutters by pre-caching terrain that is not visible on screen yet, hence resulting in a smooother and more consistent experience.

Note that the hitches / stutters discussed here are not the common stutter that happens just before touchdown in an airport, due to the sudden rendering of airport objects not previously visibile.


I agree with Archer and Marco…I’ve also found areas that will studder regardless of settings…I’ve repeatedly flown thru these areas and it does it every time. Kinda like my cell Phone…some areas more prone than others…like a dropped call lol…I have the best fiber optic LAN here also with terrific upload and download speeds…keep debating this…it has to be something server related I’m guessing


Small but important detail for me: I was running my main screen (of 3) in Windowed mode, although with the window maxed. This was causing “CPU stutters” in the in-game FPS window which disappeared when I changed that display to “FULL SCREEN”.

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If there isn’t a bug report for this you should create one!

This happens because MSFS is not a true full screen but a borderless window. Current Windows versions already handle a borderless window as full screen, so in terms of performance they are basically the same thing, but rendering priority still depends on which app window is active, so which one gets the mouse clicks or was switched by means of ALT-Tab, because MSFS is still a windowed app as the rest of standard Windows apps. Anytime MSFS does not have the priority what you are renderering indeed is the Windows desktop, that still contains MSFS as a visible windowed app. For MSFS to take rendering priority you need to click with mouse anywhere on the MSFS screen if you have multiple screens or switch to it using ALT-Tab. If you see the Windows mouse pointer on MSFS instead of the native MSFS mouse pointer (which is different and disappears after some time) then MSFS is not the active window.

You can easily check that effect if you have two monitors, you are able to set their refresh to something higher than 60 Hz as MSFS normally runs below 60 FPS (so for instance set 120 Hz) and you run game only at one of them. Open developer mode FPS counter and you will see that if you click on the second monitor (to interact with explorer or any other regular app) MSFS FPS counter will display 120 FPS, which are the FPS the Windows desktop is being rendered at, even if MSFS is still visible on the other monitor. However clicking back on game window will drop FPS back to 60 FPS or below as then MSFS is getting the priority. You can also check that with one monitor only running at 60 Hz (or any other refresh) by simply putting an small internet explorer window on top of game. While explorer is active game will display 60 FPS or the equivalent figure for your refresh and closing explorer will not change that figure. Until you click back on MSFS window the FPS value won´t go back to something below 60 FPS or the equivalent figure for your refresh.

This behaviour can easily confuse people as they may think game is running much better that it really does because, for instance, while desktop is getting priority you may not be main thread limited as FPS counter is giving a false reading and it´s always steady at its max possible FPS value. It also appears that game is running smoother, but this isn´t the case. Remember the basic rule: if you see the standard Windows mouse pointer you are not getting the real game readings in the game FPS counter.


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I have no idea of what a native MSFS mouse pointer is.

I only run FS2020 in windowed mode.
And see one mouse pointer.

Although I can Alt-Enter to switch to fullscreen, I prefer not to.

Very easy: go to mouse settings in Windows and change mouse pointer color to black or assign to it a different icon than the default one. You will see when you are at Windows desktop and when you are at MSFS, as the MSFS mouse pointer is white, a bit smaller than Windows default one and disappears after some seconds. If you still see the black mouse pointer (or the one with your changed icon) while MSFS is visible then you are indeed still at desktop (MSFS window is not yet getting the priority).

I started to use that trick of the different mouse pointers some time ago because I run G-sync and it was not working well as soon as I used the second monitor to interact with other apps. I run Littlenavmap and I display the charts in that second monitor and I frequently forgot to click back on MSFS screen after using them.


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Nice tip, because I also do this ALL the time.

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I’m always reminded to click back on the MFS monitor because when another window has the focus, the audio from MFS is silenced – pretty hard not to notice.

Isn’t muting background audio an option in settings? You should be able to toggle it off; my audio has worked fine for years while in background.

Weird. Is there some audio setting that impacts this? I’ve never lost MSFS audio when I click onto my second monitor.


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I don’t want to change it. Like I said, it’s a great reminder to give the focus back to MFS.
But thanks for pointing out that there is a setting to toggle that effect.

Other thread 1: physics, flight model
Other thread 2: audio
Other thread 3: weather calculations/ loading
Other thread 4: aircraft traffic
Other thread 5: ground traffic
Other thread 6: ATC
Other thread 7: systems

And the Main Thread to rule them all, and in the darkness bind them…

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That is absolutely not a bug. Full screen will ALWAYS perform better than windowed mode. It’s a windows issue that Asobo can do nothing about.

The problem with the whole argument about what affects what (irrespective of windowed versus full screen) is that CPU / GPU limiting is completely hardware dependent, and dependent on a ton of other factors, like, what other programs are you running, what soul sucking apps are loaded on your computer in the background that you don’t even know about, etc. etc… and whether you are running windowed or full screen. If Windows has to page anything, you’re screwed.

So there’s memory management concerns both for Asobo AND Windows. MSFS is NOT the only program running on the PC, and there’s not a whole lot Asobo can do about people who are sloppy about what else is running when they are simming. Either way, Windows has to do its own memory management on top of MSFS managing its own memory in between all that. Hence, different people will see different performance based on their rig and how they’ve set up Windows.

I’m not familiar with memory management on Xbox, but I imagine there’s issues there, too. I do know I see all the time people who do an update of the software on Xbox, and then wonder why stuff breaks or runs weird when they just fly immediately after updating without rebooting their Xbox, or at least exiting and reloading MSFS on the platform. I have no idea why, but Asobo’s updating routines are not clean, and they do not reload variables in memory everywhere. So you’re best off rebooting as soon as you finish your update on Xbox, so you can be sure you’re running with a clean memory.

Back to Windowed vs Full Screen, as soon as you go windowed, Windows has to run through all the other programs that are open on your machine, including itself. In full screen mode, the GPU is dedicated to the one program (for the most part, there’s other stuff obviously, like the nVidia game stuff that seems to always be there.)

One place I always get a long stutter is when I’m approaching an airport. I assume it’s loading the airport when you get within 5 to 8 miles away.

Smooth with no stutters in windowed mode.

4k, Ultra, Native, TAA, T LoD=600, O LoD=900.
64GB memory.
Still smooth with 16GB of memory used as a Ramdrive.


I didn’t know that!

My previous understanding was that Fullscreen and Windowed (with focus) should be the same, I didn’t realise Windows did some ‘behind-the-scenes’ things differently between the two. I thought that even when fullscreen, Windows still continued doing the other stuff out of sight.

MSFS2020 doesn’t ever play in ‘full screen mode’. What happens when you press ALT+Enter is it switches between windowed and borderless windowed mode not exclusive full screen mode of older/other games…