Help trying to diagnose stutters

It’s been getting really aggravating, as of late, flying in MSFS. It seems no matter where I fly, big city or small city, stutters will always be haunting me in the sim. I’ve tried pretty much everything I can find on the internet on how to try and suppress these stutters, but it seems nothing is working.

It’s always at the same phases of flight too where they occur. On the initial approach, it’ll seem to stutter heavily when it loads any city/ground artifacts around the area. On final approach, tons of stutters making it hard to stay stable. Especially in planes like the Fenix, where one stutter will jerk the plane in some random direction. And the most annoying of all, right before and during the touchdown. (Here’s a video showing exactly what I’m talking about, also showing the FPS counter. Pay attention to the first minute and about short final) https://www.youtube.com/watch?v=x6bJyTtJR9Y

I have a decently beefy system already. A Ryzen 7 5800x3D, RTX 2070, and 32GB 3200 MHz RAM, although I am planning on upgrading that GPU in the next week. My settings are generally medium for GPU-heavy settings and medium-high for CPU-heavy settings (ex: 100 TLOD, 50 OLOD). At this point, I’m not sure why I’m getting all these stutters. Is it my 2070 GPU holding me up? Is there some setting that I should be turning down more than it is already? I need some help trying to troubleshoot this and get an idea of what could possibly be causing all of these stutters. I notice those with similar specs seem to not have any issues like this, which makes it even more confusing and infuriating.

Any help is greatly appreciated :slight_smile:

Any overclocks?

Have you tried re-installing GPU drivers/Windows/Sim?

Background applications running? Ram useage?

Have you checked the temps for CPU and GPU?

Suspect data delivery issue, could be anything. Usual suspects:-

slow HDD
overfilled drives
fragmented drives
sleeping drives
too many drives not enough PCIe lanes
Background processes
Firewall issues
Driver issues
internet & wifi (especially if others are also using them)
cheap mobos with dodgy controllers
slow memory
etc. etc. etc.

Are you using TAA or DLSS? What settings?

In the first 30s on your video you have the explanation:

Captura de pantalla 2024-07-03 123648

  • Problem starts with a massive main thread freeze (around 1600ms)
  • At that time GPU latency is fine (around 19ms, so it could still deliver 52fps)

The problem propagates to manipulators few seconds after (I marked first problem described before and then this new one):
Captura de pantalla 2024-07-03 123335

  • Manipulators have a high latency (75ms), most likely inherited from the previous main thread freeze.
  • GPU starts to suffer the accumulated delays and starts to increase latency to 35ms (it could only deliver 28fps in this case)

Conclussion: what is freezing here is game, not your HW resources. See how memory usages are fine, near 50% in both cases. GPU is ready to render at high fps but main thread does not allow it to happen.

Only a correction on game exe can solve this issue. Freezes are a serious problem in SU15 and they were even worse with SU14 but we didn´t have so severe ones months ago. I also see them and they also last several seconds in my system (12900ks + 4090).

Cheers

4 Likes

First of all try without add-ons.

Rename community folder to community_copy.
Create new community folder.

Rename exe.xml to exe_copy.xml

Detele cache.

How to delete game cache

1 Start your PC in safe mode

  • Click start
    1start
  • Click power icon
    image
  • Press and hold left SHIFT key and click restart
    image
  • Select Troubleshoot > advanced options > startup settings > restart
  • Select 4 - Enable safe mode

2 Click start and type

%localappdata%\D3DSCache

Press Enter
Delete all folders

3 Click start and type

%APPDATA%\..\LocalLow\Nvidia\PerDriverVersion\DXCache

Press enter
Delete all files

4 Type

%localappdata%\Nvidia\GLCache

Press enter
Delete all folders

5 type

%appdata%\NVIDIAComputeCache

Press enter
Delete all folders

6 type

%localappdata%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache\SceneryIndexes

Delete all files

Restart PC

7 Click “start” and type storage settings - press enter
8 Click temporary files > scroll down > check box DirectX Shader Cache
9 scroll up > click Remove Files

10 Restart PC.

Restore Nvidia settings via Nvidia Control Panel.

How to

Restore NCP global settings

Click yes and apply.

Restore MSFS settings via program settings tab.

Click Restore > yes > apply.

Launch MSFS without 3rd party apps like FSUIPC, Spadnext, AAO, Active Sky, FSrealistic, FS2crew …

Turn off traffic via traffic settings and all sliders to 0.
Turn off traffic and multiplayer via data settings.
Delete and turn off rolling cache.
Apply and save.

Select Cessna 152 or 172 and departure > fly

1 Like

Yeah in something like 1/3 of all sessions I get these big CPU spikes causing a big stutter once every 20-60 seconds or so. It’s not hardware related, it’s not even really a performance problem. It’s a glitch in the sim that (luckily) only manifests in 1/3 or so of my flights. It’s not related to plane, scenery, Server, or settings, apart from terrain LOD. Turning terrain LOD way down reduces the severity the more you turn it down, which is not a viable solution.

This seems to have started with SU14, I’ve seen a lot of people report it. In the other 2/3 of sessions, the sim runs near perfectly. Smooth and no stutters, very fluid.

Do you also find that it only happens on certain days, not all the time?

Also see my thread here that I just started and feel free to contribute:

And an older one:

It´s a problem of the game code so don´t look for any other explanation as you will only lose time trying to diagnose it and changing your systems for nothing. The major freeze is caused by a distant city which is loaded in one go. This is how Asobo decided that scenery was going to be managed in game and that, together with an object size based LOD policy, results in big buildings being rendered all at once first, followed by smaller objects, which are loaded short after that as soon as their lowest detail LODs meet the requirements to be displayed: basically they use more pixels on the screen (so they are bigger) than the minimum pixel size defined for LOD switching.

Therefore this is not a problem caused by user´s systems, as even faster systems will face a sudden workload that conceptually has no sense, as scenery could be loaded progressively instead of pretending to load it in one go. Faster systems may be lucky to deal with the problem faster but this will still result in a microfreeze instead of a longer freeze. Those microfreezes are still freezes caused by code nature but they are simply much shorter. On the other hand reducing graphical quality settings will just result in problem happening later (closer to player) but will still happen when city needs to be rendered. Drivers, Windows reinstallations, game reinstallation, addons removal and all that stuff won´t fix a problem which sits at code level.

You can see this behaviour at OP´s video, between seconds 30-35. Manipulators thread, which in principle is the one that handles objects updating and rendering, and game´s main thread suffer a freeze of 1.6 seconds (1600 ms latency in the FPS graph). In video you can also see freezes lasting 5 seconds (5000 ms).

This is what happens before the 1600ms freeze. I marked the city area in green. Here city is not yet rendered because the threads are still managing the city objects. This event is what causes the freeze. Indeed manipulators thread is the first that generates the bottleneck and very short after that main thread is also blocked. I noticed this after having watched the video for a second time, sorry.

This is what happens after the city is loaded and displayed. The latencies are reduced (manipulators thread latency drops to 75ms, which is still high anyway), but as they delayed the whole simulation during 1.6 seconds the rest of pending tasks which were expected to happen after displaying the city are also delayed and everything else becomes blocked until whole simulation is balanced again. That leads to a concatenation of freezes that add yet more delays until main thread and manipulators thread are able to solve all pending tasks so that game can run normally for some time. Then situation is repeated over and over again and results in what is seen in video.

Cheers

5 Likes

No overclocks. Especially with my 5800x3d, overclocking is the last thing I’d ever do to that CPU. I’ve reinstalled drivers, the sim once, and windows once before. Nothing helped it. Background applications, nothing too significant. RAM usually sits in the mid to upper 20’s out of a total 32. Temps are both sitting mid 70’s to low 80’s.

Thanks to all of these replies and information everyone. So what I’m getting out of this is MSFS is generally just optimized so poorly that even higher end systems experience similar issues? Would seem reasonable since MSFS is the only game I’ve ran that experiences heavy stutters or lag like this, despite my decently high performing rig. I guess my best decision is to hope MSFS 2024 fixes the logic behind how the sim renders these objects and improve these stutters. I would’ve hoped Asobo could’ve figured it out by now, but I guess it’s up to 2024 to (hopefully) fix these problems.

What worries me is I’m not even sure they are aware how bad it is as their only concern is getting a vanilla sim to run. They don’t really test in real scenarios with many other apps and services running that real users use in real flights and in multiplayer group sessions and in longer flight sessions or legs / trips etc in heavy (performance wise) aircraft.

And their in-house QA team has historically let some real obvious stuff slip through to live (and regressions) as if not even checked at a basic level, so I cannot see the stars suddenly aligning for us to end up with a robust system that still has enough headroom to let us run the sim in a real scenario and in the way we prefer to spend our time flying in - in the reality of the hobby and how we use this software + mods + plugins + hardware.

I massively hope I’m wrong!!!

4 Likes

To be fair it´s not the only one. Unreal games still suffer a lot due to shaders compilation and tile loading, especially the ones using UE 4. But even recent titles using UE 5 also have issues.

However MSFS is the only one I know where you don´t see a clear performance consolidation curve, meaning that each SU can keep previous figures or can improve them. Each SU can either produce really good results or simply go back to terrible performance that you already saw months ago. When performance improves is because it was previously degraded somehow, which is not a real step forward but simply a restoring to a previous step.

We are always dancing around a platform limitation that won´t be ever solved with current technical solution, no matter which magic formulas devs try to invent. It would be better if they just accept that game can´t do more than that and correct the exisiting bugs at that level. At least that would result in a stable release that works well, keeps working well and can be used normally for months till the end of its effective life.

Cheers

After over a year of having solid performance with no stutters, the past week after the AIRAC update, I’m now getting stutters every couple of seconds.

I have an overpowered PC with a i9 14900, RTX 4090 and 128GB of RAM. There is no reason other than Asobo that I’d be getting these freezes with such massive headroom on performance. Funny thing is, I also get these when I’m in the menu with rendering paused.

Wow that’s exactly what I am getting. I normally fly the A32NX in development mode and the stutters are just like your post. But if I fly in stable mode its nearly not there ?

in my experience, the main thread always locks up when loading data, although in a normal situation this is barely noticeable, they are like micro-freezes
for some people, this loading process goes cuckoo… and the microfreezes turn into a 5 second stutter… which of course, is unacceptable

the first thing i would try is to run the game clean of ANY and ALL 3rd party addons, particularly live traffic injection addons if you have them

then, check the settings of your virtual memory paging files, make sure you dont have one somewhere absurd, like a network drive or an old hdd thats in power down mode

lastly, this software is very. very sensitive to memory stability, although it usually manifests as ctd’s, but its worth a try, make sure your memory is super stable, a quick and dirty way to check this is to downclock it to a lower speed, although it would need further investigation

1 Like

Just to say I really appreciate your analysis of the situation. I was away from MSFS for a month and came back to a sim update and now have constant pauses throughout a flight. I’ve been trying to figure out why but seeing this thread, and your posts, reassure me, not in a positive way, that Asobo have once again fiddled where they shouldn’t have and screwed the performance. A couple of Sim Updates ago, things were so smooth and peachy and now it’s a bit of a mess again.