Stumbled Upon Potential Solution to Stuttering/Stability Issues

User Support Hub Hardware & Peripherals
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Dear Community,

It is possible that I’ve stumbled upon a solution to stuttering and stability issues with MSFS, and I want to share. Performance has been bugging me so much that I spent the whole weekend testing different configs, with and without AMD tuning. I have also tried (probably) all the various tweaks and optimizations that people have made available online, and none of them have really helped, apart from framerate limiting.

Ultimately, what really worked in terms of getting rid of stutters (for the most part, subjectively like 90% gone), was simply:

  1. Leave the Nvidia settings at default, including power management, apart from the global settings adjustment for 3FPS lower than my monitor refresh rate.

  2. Set sim settings to Ultra.

  3. Increase render scaling to 105.

  4. Set Vsync to On in-game and set the value to 20.

  5. Delete and turn off the Rolling Cache.

That’s it! This is what worked for me and others’ mileage may vary with this approach. Now the experience is amazingly smooth and stutter free and stable. I did not have a single CTD across two 3-hour sessions with the sim so far, and no performance degredation.

GENERAL THEME THAT MAY BE APPLICABLE TO ALL PERFORMANCE HUNTERS

From the experience I gathered across my almost 12 hours of testing, sadly I did not record clearly what I did for review and reference and I wish I had, the stutters seem to come when the sim is heavily limited by the mainthread. Hence, my hypothesis is that the objective of tweaking and optimizing for anyone, should be to find a graphics setting that works for you in general, then lower the framerate (using in-game vsync, Nvidia frame limiting and vsync didn’t help as much as ingame vsync) and increase the load on the GPU (through render scaling manipulation) until the sim performance is relatively limited by the GPU and green or yellow at most when limited by mainthread. Testing was conducted at Jeddah’s King Abdul Aziz and NYC’s JFK, two airports where I find the most amount of instability and stuttering, and experience the most number of crashes, again subjectively remembered, I haven’t recorded data to present objectively.

Everything else (sim and Nvidia) is at default settings, along with game mode turned off in Windows settings. Along with this, my CPU is tweaked with AMD overclocking so that gets better performance (objectively measured with benchmarks and 12 hours of stress testing).

For reference and anyone who’s interested, my system is:

Ryzen 5800X - PBO optimized and regularly boosting to 5Ghz and sustained at 4.85Ghz during flight sim.
Nvidia 3080 - Gigabyte Gaming OC - Stock config on OC vBIOS
32GB of 3200mhz CL 16 memorry (8x4) overclocked-stable-stress tested to 3400mhz CL15
32GB Fixed size page file
Samsung 970 EVO 1TB - System Drive - MSFS installed on System Drive
All Nvidia Settings at Default except global framerate limiter to 117FPS
3440x1440 G-Sync Capable (Native) Display (120hz) with G-Sync enabled.
Windows 10 tweaked to be clean and light with all non-essential services either disabled or set to manual.

I also stumbled upon this post (NDU registry change) Increase performance immediately! AMAZING! - #197 by GONEFLYING1234 which I look forward to also trying the next time I have time to sim.

Thanks for reading and I welcome any feedback from anyone who tries what worked for me, whether successful or not.

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With a 120Hz refresh rate, that’ll give you 40 FPS. I use 30 FPS on my laptop to keep temperatures down.

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Yep, that’s correct. It works for me as without vsync enabled in-game I get between 50 and 70 FPS, everywhere except JFK and LAX. However, it’s heavily limited by mainthread all the time and there’s plenty of stuttering as framerates fluctuate all the time. For some reason gsync isn’t able to smooth it out, and I don’t know why. I’ve tried other titles like farcry and cyberpunk and both those too have hugely fluctuating framerates, but there’s never any stuttering or tearing. And I’ve confirmed that Gsync is in fact enabled and working when MSFS is active.

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Since MSFS is heavily CPU bound, the graphics render queue can drain empty and the graphics driver won’t have enough data to smooth out.

That’s a good tip as it helps prevent the render queue from draining and stalling the GPU. However it can drive up GPU temperatures which is something I’m actually trying to avoid on my laptop.

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In general LOD’s (TLOD/OLOD) and AI traffic (air, ground, airport worker & traffic) & ultra clouds hit CPU the most and can create mainthread limited situations, if you see this at all, lower these values a bit, while increasing GPU load via the other graphical sliders or if you run out of them use render scale (as you have done). GPU needs to be loaded/balanced.
Did you try the NVidia settings in the Pilot Pete smoothness video? Seems like one of these settings really helps I suspect the texture and low latency mode ones. I have my setup at 30FPS/60Hz refresh rate and its very smooth. very minimal stutters even in scenery dense airports. Stutters at JFK and LAX and probably EGLL and LFPG are worst case on CPU TLOD wise so tune your system while parked there on the ground. It may involve accepting a TLOD of 200. But try the NVCP tweaks below as they do work. They should be made in a FS2020 profile in NVCP, not your global settings.
This locks me on 30FPS(60Hz) with extremely smooth performance.

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Low latency mode reduces the amount of commands queued to the GPU, so the queue will drain faster and the GPU will stall more often, which usually decreases smoothness.

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I don’t see any issues with Low Latency Mode, but I’ve seen various takes on it anywhere from OFF to ON to Ultra. I would need to specifically experiment. The settings listed are as per pilot pete’s smoothness video.

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Thank you for your feedback. I will look into it.

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I don’t know who Pilot Pete is, but NVIDIA has forever stated in their control panel that more pre-rendered frames is usually smoother and maximizes throughput.

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It could be that low latency mode works best ON with the VSync 30FPS/60Hz settings as described, but would need to check what happens in the various low latency modes. I currently have such smooth performance though that it would be hard to notice a further improvement. I also did the NDU tweak and again hard to notice, but it seems even faster now. My metric being how fast/smooth it is to pan quickly around in the cockpit view of say the CRJ parked at Heathrow. Another metric being panning to side view during takeoff. Nail those and you are indeed on top of the worst case FS graphical scenarios, and sim will be smooth everywhere else. The pilot pete video is here for ref-

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Yep, no need to mess with what works.

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This bit is intereting to me as it says CPU would be dishing out 3 frames with low latency mode ‘OFF’ yet just 1 frame with it ‘ON’-
“With the default (LL) settings off, the game’s engine will queue one to three frames at a point. The ON setting will force the game to only queue a single frame, which is equal to setting Max_Prerendered_Frames to 1 in older NVIDIA drivers. The Ultra setting submits the frame just in point for the GPU to choose it up—there will be no frame sitting in the queue and waiting.” ref here

It’s all very counter intuitive, but much of FS tweaking is as it’s certainly no 60FPS first person shooter.

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Imagine there are 3 frames worth of commands sitting in the GPU render queue, while the GPU is processing its current frame. Now imagine a CPU bottleneck coming along and stalling the pipeline for 3 frames worth of time. The GPU could have been busy displaying those 3 frames in the queue while the CPU caught up, smoothing out the CPU bottleneck. Now run the above scenario again with only 1 pre-rendered frame. The GPU stalls.

The real problem is MSFS is so CPU-bound that the above 3-frame scenario might not even occur very much in practice.

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I can see what you mean there. Everywhere I read says LL mode is meant for GPU limited scenarios and high FPS games, so what you say stacks up in theory. I don’t have an explanation of why it works. I may try it on the 3 LL settings/modes and compare things. It could be that Pilot Pete had a lesser system at the time of publishing so may have been GPU limited (He lists a Intel i7-6700K @ 4.7 GHz, GTX980Ti 6GB). I just know that it works on my higher end GPU. It could be that LL isn’t the factor though and the 30PFS/60Hz and the NVCP ‘performance’ texture settings are the real factors in my performance/smoothness.

Now that is a great question. Yes CPU bound and everyone given an TLOD slider that goes to 400, what could go wrong :sweat_smile:

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My NVIDIA driver profile is pretty much default except I have background max FPS set to 20, Anisotropic sample optimization on, Threaded optimization on. On the Global tab I have Shader cache size on Unlimited. But since I’m on a laptop I am balancing performance and temperatures so I left power management mode on Optimal and limit to 30 FPS using RivaTuner FPS limiter (front edge sync + passive waiting).

I’m pretty confident in all of my settings except for the Threaded optimization. More testing is needed on my part so I wouldn’t necessarily recommend changing that one.

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Probably a good idea limiting GPU frames for laptop. I had my newish (business) laptop (before I read about the 30FPS/60Hz trick which I’m now using on my desktop) at 100% GPU running FS for 3 months. I was heavily GPU limited on the laptop as it only had a equiv of a 1060 card, but the GPU fan bearings took a bit of a hit in those 3 months, and can make a strange noise sometimes now. You have to limit frames somehow though as even FS menus will run at 140FPS and 100% GPU if you let them go there on default settings. It’s not much wonder users are bewildered by all these issues. I am and I’m fairly tech savvy.

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another thought I just found on my system. Ive bn having poor fps and ctd for a couple weeks. turned out to be my HDMI cable. PC runs fine in desktop with simple programs. start up a high graphics game and it goes crazy. replaced the cable and wow. feels like a new pc. just found out its not only software settings that matter.

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Especially with 4K and HDR, but yes don’t discount cables the cables. I’m using HDMI 2.1 UHD to a OLED TV and I needed a good HDMI cable for that. My TV doesn’t have the display port option so I can’t comment on that type of cable.

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You sound like me with my broken USB mouse cable causing the simulator to keep crashing to desktop :sweat_smile: It took me a while to figure that one out.

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I tried the settings listed by the OP. Not only did I have even worse stutters, but my FPS was hard to deal with. :nauseated_face: Best of luck to everyone else though.

i9-10850k @ 3.60, RTX3070, 32 gig