Another post of Stuttering.

[Dwail_Hicks]

Hello. First of all, I have a good computer: I7-9700K, RTX 3080 12 GB, 32 GB RAM. The problem is the following:

 

I have been able to check after a while fiddling with the different game modes (quick battle, missions, campaigns, career), when I start a campaign and start playing, even though the computer tells me that the game is running at 80 fps, I see an annoying stuttering of images when rotating the camera. I only notice stuttering when starting any mission in campaign mode; in quick battle, missions and career modes it is not noticeable: the difference in fluidity of these modes with that of any campaign is very visible. What could this be due to, the game engine? Is it possible that when the game has to manage many units on the map, the performance drops, even though the number of fps it counts remains the same?

 

NOTE: Doesn't matter if graphic settings are at Max or Low quality.

[GlobFly]

I notice really bad stuttering in IL-2 on a pretty high end PC as well, 9900k. 3080 Ti, 32gb, nvme SSDs. No matter what settings I use - seriously, even the lowest settings you can select in the game - the game randomly stutters really, really badly. *fps* is just fine, 80+ most of the time even with max settings @ 4k, but it's the frame *pacing* / stutters that get really bad. They seem far worse in the more recently recently released maps like BoP but they do happen in BoS, BoM, BoK too.

 

I've spent so much time trying to figure out a solution but it seems it's something "baked" into the game/engine somewhere at this point. I really hope the devs can address this.

[354thFG_Drewm3i-VR]

This is a game engine problem only solved by better hardware. You both have very good gpus, but your cpus are very dated Skylake chips in need of upgrading to play single player without time dilation (which you are calling stuttering).

 

Pick up a Ryzen 5800X3D/7000 or Intel i5/i7 12th/13th gen paired with 32 GB of fast ram with tight timings and you'll see a big uplift.

[dgiatr]

16 minutes ago, drewm3i-VR said:

This is a game engine problem only solved by better hardware. You both have very good gpus, but your cpus are very dated Skylake chips in need of upgrading to play single player without time dilation (which you are calling stuttering).

 

Pick up a Ryzen 5800X3D/7000 or Intel i5/i7 12th/13th gen paired with 32 GB of fast ram with tight timings and you'll see a big uplift.

...i have the same problem too with stuttering although i get more than 85 fps most of the time in multiplayer. I own an advanced gpu ( 3090 ti ) with outdated cpu ( i5 10600k ). Its happens especially when i fly over crowded places with many objects lying all around....

 

.....can anybody explain to me why i get stuttering although i have high fps?

 

Thanks... 

[Youtch]

They were report of windows 11 update causing some stuttering, with a workaround proposed.

[dgiatr]

6 minutes ago, Youtch said:

They were report of windows 11 update causing some stuttering, with a workaround proposed.

i still use win 10...

[GlobFly]

12 hours ago, drewm3i-VR said:

This is a game engine problem only solved by better hardware. You both have very good gpus, but your cpus are very dated Skylake chips in need of upgrading to play single player without time dilation (which you are calling stuttering).

 

Pick up a Ryzen 5800X3D/7000 or Intel i5/i7 12th/13th gen paired with 32 GB of fast ram with tight timings and you'll see a big uplift.

Well I just ordered a 5800X3D + X570 mobo so we'll see if it indeed cures the stutters or not. I will report back with my findings.

[firdimigdi]

On 11/6/2022 at 4:16 PM, Dwail_Hicks said:

Hello. First of all, I have a good computer: I7-9700K, RTX 3080 12 GB, 32 GB RAM. The problem is the following:

 

I have been able to check after a while fiddling with the different game modes (quick battle, missions, campaigns, career), when I start a campaign and start playing, even though the computer tells me that the game is running at 80 fps, I see an annoying stuttering of images when rotating the camera. I only notice stuttering when starting any mission in campaign mode; in quick battle, missions and career modes it is not noticeable: the difference in fluidity of these modes with that of any campaign is very visible. What could this be due to, the game engine? Is it possible that when the game has to manage many units on the map, the performance drops, even though the number of fps it counts remains the same?

 

NOTE: Doesn't matter if graphic settings are at Max or Low quality.

 

15 hours ago, GlobFly said:

I notice really bad stuttering in IL-2 on a pretty high end PC as well, 9900k. 3080 Ti, 32gb, nvme SSDs. No matter what settings I use - seriously, even the lowest settings you can select in the game - the game randomly stutters really, really badly. *fps* is just fine, 80+ most of the time even with max settings @ 4k, but it's the frame *pacing* / stutters that get really bad. They seem far worse in the more recently recently released maps like BoP but they do happen in BoS, BoM, BoK too.

 

I've spent so much time trying to figure out a solution but it seems it's something "baked" into the game/engine somewhere at this point. I really hope the devs can address this.

 

Seems like you are both encountering the situation described below which I erroneously thought was a VR issue initially and later on postulated that it might occur also with higher-than-60Hz monitors. It seems to be a CPU-bound bottleneck of sorts in the game engine which indeed can be mitigated by throwing a stronger CPU at it but I have my reservations as far as this being actually the correct approach - it simply moves the goal post a bit further. For more you can read some of my findings in the thread:

 

 

[GlobFly]

16 minutes ago, firdimigdi said:

 

 

Seems like you are both encountering the situation described below which I erroneously thought was a VR issue initially and later on postulated that it might occur also with higher-than-60Hz monitors. It seems to be a CPU-bound bottleneck of sorts in the game engine which indeed can be mitigated by throwing a stronger CPU at it but I have my reservations as far as this being actually the correct approach - it simply moves the goal post a bit further. For more you can read some of my findings in the thread:

 

 

The thing is, if it was just a case of being CPU bound, limiting frames to well below the CPU's frametime should reduce the problem or eliminate it completely, but it doesn't, at least not on my system.

 

There are at least a couple of factors compounding the issue, though. For one thing, the code that controls certain things like "cinematic mode" camera movements, F11 free camera zoom, the F3 flyby camera movements, etc all seem to update independently of framerate at a locked 50hz. That means that unless the sim is running at exactly 50fps with perfect framepacing, there's a lot of induced stuttering in F2 view, F3 view, F11 view, and some other situations. Further exacerbating this perceived stutter when not at 50fps is the motion blur shader that cinematic camera mode uses - because motion blur shaders rely on frame-to-frame data, it basically breaks at anything but 50fps, causing persistent/double frames or missing motion blur between frames. This is only a small part of the larger problem though.

 

Let's say I reduce CPU-heavy settings (distant buildings, terrain complexity, etc) way down and limit FPS to 50, the sim will *still* manifest some severe stutter problems, seemingly at random. While I haven't found any actual fix, one thing of note I came across is that pressing tab to show the mission summary overlay will often sort out the stutters - at least for a short while. I'd say this indicates a problem with threading and optimization rather than just "the sim is doing so much stuff at once, it's just a limitation." Especially as you said in your thread, the sim didn't do this in the past (I've only just recently reinstalled IL-2 after having not played it for quite some time.)

Edited December 2, 2022 by GlobFly

[firdimigdi]

34 minutes ago, GlobFly said:

The thing is, if it was just a case of being CPU bound, limiting frames to well below the CPU's frametime should reduce the problem or eliminate it completely, but it doesn't, at least not on my system.

 

There are at least a couple of factors compounding the issue, though. For one thing, the code that controls certain things like "cinematic mode" camera movements, F11 free camera zoom, the F3 flyby camera movements, etc all seem to update independently of framerate at a locked 50hz. That means that unless the sim is running at exactly 50fps with perfect framepacing, there's a lot of induced stuttering in F2 view, F3 view, F11 view, and some other situations. Further exacerbating this perceived stutter when not at 50fps is the motion blur shader that cinematic camera mode uses - because motion blur shaders rely on frame-to-frame data, it basically breaks at anything but 50fps, causing persistent/double frames or missing motion blur between frames. This is only a small part of the larger problem though.

 

Let's say I reduce CPU-heavy settings (distant buildings, terrain complexity, etc) way down and limit FPS to 50, the sim will *still* manifest some severe stutter problems, seemingly at random. While I haven't found any actual fix, one thing of note I came across is that pressing tab to show the mission summary overlay will often sort out the stutters - at least for a short while. I'd say this indicates a problem with threading and optimization rather than just "the sim is doing so much stuff at once, it's just a limitation." Especially as you said in your thread, the sim didn't do this in the past (I've only just recently reinstalled IL-2 after having not played it for quite some time.)

 

Yes I simplified my description here for brevity's sake as I've written too much on the subject. My pet theory is that the issue is a result of thread locking. As in a thread is stalled waiting on something (likely another thread) to complete. If you read that forum thread I linked towards the end I have pointed to a possible culprit.

Edited December 2, 2022 by firdimigdi

[GlobFly]

1 hour ago, firdimigdi said:

 

Yes I simplified my description here for brevity's sake as I've written too much on the subject. My pet theory is that the issue is a result of thread locking. As in a thread is stalled waiting on something (likely another thread) to complete. If you read that forum thread I linked towards the end I have pointed to a possible culprit.

My findings seem to line up with what you've found. The tab key thing, I assume, results from the Scaleform thread you mentioned, and I forgot to mention in my reply above that I also noticed some interesting behavior related to toggling the cinematic camera on and off. That should have nothing to do with stuttering, yet I frequently could eliminate (or induce) stutters by turning that option on or off, at least for a time.

 

Has the developer ever responded positively to any of this?

[354thFG_Drewm3i-VR]

5 hours ago, GlobFly said:

Well I just ordered a 5800X3D + X570 mobo so we'll see if it indeed cures the stutters or not. I will report back with my findings.

Pair that with Patriot cl14 ram and you're good to go!

4 hours ago, GlobFly said:

The thing is, if it was just a case of being CPU bound, limiting frames to well below the CPU's frametime should reduce the problem or eliminate it completely, but it doesn't, at least not on my system.

 

There are at least a couple of factors compounding the issue, though. For one thing, the code that controls certain things like "cinematic mode" camera movements, F11 free camera zoom, the F3 flyby camera movements, etc all seem to update independently of framerate at a locked 50hz. That means that unless the sim is running at exactly 50fps with perfect framepacing, there's a lot of induced stuttering in F2 view, F3 view, F11 view, and some other situations. Further exacerbating this perceived stutter when not at 50fps is the motion blur shader that cinematic camera mode uses - because motion blur shaders rely on frame-to-frame data, it basically breaks at anything but 50fps, causing persistent/double frames or missing motion blur between frames. This is only a small part of the larger problem though.

 

Let's say I reduce CPU-heavy settings (distant buildings, terrain complexity, etc) way down and limit FPS to 50, the sim will *still* manifest some severe stutter problems, seemingly at random. While I haven't found any actual fix, one thing of note I came across is that pressing tab to show the mission summary overlay will often sort out the stutters - at least for a short while. I'd say this indicates a problem with threading and optimization rather than just "the sim is doing so much stuff at once, it's just a limitation." Especially as you said in your thread, the sim didn't do this in the past (I've only just recently reinstalled IL-2 after having not played it for quite some time.)

Good post. Thanks for the technical info.

2 hours ago, GlobFly said:

 

 

Has the developer ever responded positively to any of this?

Yes, the devs recently alluded to planned engine optimizations going forward so its safe to say they're aware.

[firdimigdi]

14 hours ago, GlobFly said:

Has the developer ever responded positively to any of this?

 

Not for the current engine. Closest we got was some mention in a livestream that the next one will have a different UI middleware (Noesis from what we know from their recruitment ad in the Russian forum) allowing for better performance. But nothing about this being clearly acknowledged either as a problem that will receive attention or even as an unsolvable one that will remain.

 

14 hours ago, GlobFly said:

toggling the cinematic camera on and off. That should have nothing to do with stuttering, yet I frequently could eliminate (or induce) stutters by turning that option on or off, at least for a time.i

 

It toggles some effects (vignette, motion blur, lens flare, etc) so perhaps in some cases the effect is applied in error and toggling it causes the game to correctly disable them. In one update that I can recall there was an issue that got hotfixed where the vignette (at least) was applied also to the cockpit camera.

 

The TAB thing you mention is interesting. I recall trying various combinations of UI-related options and overlays to see if it reduced at some point the CPU time used by the Scaleform function I saw without any tangible differrence. Will give it another go at some point to see if I missed something.

 

 

 

Edited December 3, 2022 by firdimigdi

[dgiatr]

2 hours ago, firdimigdi said:

 

Not for the current engine. Closest we got was some mention in a livestream that the next one will have a different UI middleware (Noesis from what we know from their recruitment ad in the Russian forum) allowing for better performance. But nothing about this being clearly acknowledged either as a problem that will receive attention or even as an unsolvable one that will remain

 

 

 

I agree that Devs have to do something about that, they cannot pretend like nothing is happening which is very frustrating. Yesterday i tried to fly in Finnish with my G2 Vr headset and while i had about 80 or 85 or even 87 fps i got some very disturbing stuttering breaking any kind of immersion you want to have at that time! I think that the problem gets bigger with last updates......i wish Jason was here.....

Edited December 3, 2022 by dgiatr

[IckyATLAS]

On 11/6/2022 at 3:16 PM, Dwail_Hicks said:

I only notice stuttering when starting any mission in campaign mode; in quick battle, missions and career modes it is not noticeable

Which map does cause more this effect?

When you start a mission if the map is loaded with a lot of objects it takes time until everything is loaded. In some cases, you can consider at least 30 seconds in large maps.

After the start of the mission do nothing and wait 30 to 40 seconds, then unpause the game and start playing. Do you have the same problem?

 

[GlobFly]

3 minutes ago, IckyATLAS said:

Which map does cause more this effect?

When you start a mission if the map is loaded with a lot of objects it takes time until everything is loaded. In some cases, you can consider at least 30 seconds in large maps.

After the start of the mission do nothing and wait 30 to 40 seconds, then unpause the game and start playing. Do you have the same problem?

 

it doesn't matter for me, no matter how long i might wait before starting. there is always some amount of stuttering

[356thFS_Piranha]

I've been following this topic. 

My system is a 3080ti with 32 gigs of DDR5 and a I9-13900 CPU.

I've noticed micro stuttering when looking in the cockpit and sometimes major stuttering that clears up after a reboot but the micro stuttering is always there .

My FPS is 70-90 range. 

What I noticed recently is if I drop to 60HZ from 90HZ all stuttering is completely cleared up. I haven't noticed anyone on this forum mention this. I might have missed it.

I have good visual at 60hz but it would be nice to play at 90HZ. 

This comment probably doesn't help solve the issue but I thought I would throw it in here anyway.

[GlobFly]

1 hour ago, 86th_Piranha said:

I've been following this topic. 

My system is a 3080ti with 32 gigs of DDR5 and a I9-13900 CPU.

I've noticed micro stuttering when looking in the cockpit and sometimes major stuttering that clears up after a reboot but the micro stuttering is always there .

My FPS is 70-90 range. 

What I noticed recently is if I drop to 60HZ from 90HZ all stuttering is completely cleared up. I haven't noticed anyone on this forum mention this. I might have missed it.

I have good visual at 60hz but it would be nice to play at 90HZ. 

This comment probably doesn't help solve the issue but I thought I would throw it in here anyway.

I'll give 60 hz a try. I have a 120hz display and rarely run anything other than 120hz, but it might be a useful clue for the devs if it does make a difference.

 

edit: Tried 60hz. No difference in stuttering compared to 120hz, whether locked at 60 fps via Vsync or not

Edited December 3, 2022 by GlobFly

[GlobFly]

Jeez, with the settings at absolute minimum, the game looks like a potato (as expected) and FPS are super high but it just stutters so bad. Can devs please comment on this??

[IckyATLAS]

On 12/3/2022 at 1:52 PM, GlobFly said:

it doesn't matter for me, no matter how long i might wait before starting. there is always some amount of stuttering

One test that you can try is first to compare with the QMB how the stuttering behaves on the Lapino winter map and on the Kuban, Rheinland or Normandy summer Maps.

Have your graphic parameters set to a high level with MSAA antialising set to 4. In each map fly a mission with multiple planes (Use the same number and type of planes in all maps). Then check how stuttering is when you move your camera inside your plane as pilot, then hit F2 and do the same with the camera, then hit F11 and again look around with your camera. Do you see exactly the same stuttering when you are in the plane and looking around from your cockpit window and when you are a free floating camera (F11). You can also try after hitting the F11 key, to move the camera keeping the 0 key of your numerical keyboard pressed which will slow the camera motion and see if  it improves.

Do the test with each map and compare. Lapino is a very small map compared to Normandy or Kuban. By having multiple planes you load additionally the system but the same additional load with each map. If there are differences then we may get an idea about what happens.

[GlobFly]

Well my 5800X3D and motherboard are here so I'm about to start installing it. I'm hopeful that it "brute forces" through the problem but I'm kinda worried that it's some other problem (perhaps related to Windows 11 and its slight difference, drivers, things like that.) But either way, I'll report my findings here.

[GlobFly]

Well, my new PC is up and running with a fresh install of Windows 11 22H2, and while there's obviously an improvement to overall framerate, there's *still* a seemingly random stutter problem. Just as with my previous PC, there's a stuttering that can start happening at random, and it seems that pressing tab or alt-tabbing back and forth between another window and IL-2 makes it stop - for a while. Again, like before, this happens no matter how low or high my IL-2 graphics settings are.

 

I'm 100% confident there's some sort of bug at play here, maybe swapchain related or some other issue related to game/window management.

Edited December 8, 2022 by GlobFly

[MarcoPegase44]

Hello,

I am not a computer expert.

I had the same problems and tried many settings.

In fact I realized that some remaining badly uninstalled mod files can reduce the performance of the game. And I use the minimum of MOD.

In addition, I favor graphics card adjustments which let the application manage the settings and not the card settings.

Just by doing this I have gained a lot on stuttering problems.

[GlobFly]

33 minutes ago, MarcoPegase44 said:

Hello,

I am not a computer expert.

I had the same problems and tried many settings.

In fact I realized that some remaining badly uninstalled mod files can reduce the performance of the game. And I use the minimum of MOD.

In addition, I favor graphics card adjustments which let the application manage the settings and not the card settings.

Just by doing this I have gained a lot on stuttering problems.

I don't use any mods at all.

[GlobFly]

I dunno if developers have any interest in checking this problem, but I have discovered some useful info, probably best for whoever at 1C handles renderer and related coding.

 

I used a free utility called "Special K" (website here Tools | Special K - The Official Wiki (special-k.info) ) to play around with swap chain and other settings (flip discard on vs off, different numbers of prerendered frames, etc) and after hours and hours (and hours...) of trying different iterations of Special K settings along with certain Windows settings like the new "fullscreen optimizations" and Auto HDR features of Windows 11, I found the following to be the most 'impactful' change that got me right back to the MUCH smoother IL-2 experience that I was familiar with:

 

If you disable the flip discard presentation mode and then force exclusive fullscreen mode using SK, while having IL-2's "fullscreen" option UNCHECKED, I immediately saw it running much smoother - in fact, with perfect frame pacing with every IL-2 setting maxed out, even with a pretty heavy ReShade preset running as well. The only thing that could still cause frame pacing to be a bit 'juddery' was playing a really heavy mission on the Bodenplatte map, like the P-51D bomber escort mission, but even then it was vastly improved over how it was.

 

TL;DR here is that there's probably some kind of conflict right now between the current version of IL-2 and the recent builds of Windows 11 (possibly Windows 10's recent builds as well, although I can't test that) and its relatively recent inclusion of the new presentation mode setting. There's an article from February on the DirectX developer blog that touches on it briefly: Updates in Graphics and Gaming - DirectX Developer Blog (microsoft.com)

 

That being said I did try turning off the feature for IL-2.exe but it did not have an effect; nevertheless I think this is probably a good lead that should be investigated further.

Edited December 12, 2022 by GlobFly

[Tchandour]

On 12/12/2022 at 5:39 AM, GlobFly said:

I dunno if developers have any interest in checking this problem, but I have discovered some useful info, probably best for whoever at 1C handles renderer and related coding.

 

I used a free utility called "Special K" (website here Tools | Special K - The Official Wiki (special-k.info) ) to play around with swap chain and other settings (flip discard on vs off, different numbers of prerendered frames, etc) and after hours and hours (and hours...) of trying different iterations of Special K settings along with certain Windows settings like the new "fullscreen optimizations" and Auto HDR features of Windows 11, I found the following to be the most 'impactful' change that got me right back to the MUCH smoother IL-2 experience that I was familiar with:

 

If you disable the flip discard presentation mode and then force exclusive fullscreen mode using SK, while having IL-2's "fullscreen" option UNCHECKED, I immediately saw it running much smoother - in fact, with perfect frame pacing with every IL-2 setting maxed out, even with a pretty heavy ReShade preset running as well. The only thing that could still cause frame pacing to be a bit 'juddery' was playing a really heavy mission on the Bodenplatte map, like the P-51D bomber escort mission, but even then it was vastly improved over how it was.

 

TL;DR here is that there's probably some kind of conflict right now between the current version of IL-2 and the recent builds of Windows 11 (possibly Windows 10's recent builds as well, although I can't test that) and its relatively recent inclusion of the new presentation mode setting. There's an article from February on the DirectX developer blog that touches on it briefly: Updates in Graphics and Gaming - DirectX Developer Blog (microsoft.com)

 

That being said I did try turning off the feature for IL-2.exe but it did not have an effect; nevertheless I think this is probably a good lead that should be investigated further.

I'm very glad to see research on this very frustrating problem. The trick I've bolded your message quoted above, is it complicated to pull off? I'd like to try it and a quick Googling didn't take me very far.

Edited December 14, 2022 by Tchandour

[IckyATLAS]

On 12/14/2022 at 11:52 AM, Tchandour said:

quick Googling didn't take me very far.

Maybe time to try ChatGPT who knows?

[GlobFly]

alright, i have to amend my post/solution above, and what i think the source of the problem is. to put it very simply, it seems like the 'lower framerate while window is not focused (user alt-tabbed away)" feature that seems to exist in IL-2 creates a problem when tabbing back to the game window every so often, approx one in 5 times maybe. it seems like main game sim/update thread gets out of sync and the only thing that can fix it is alt-tabbing away and back again until it "re-syncs" and is fine. when it "de-syncs" it manifests as long dropped frames (stutters.)

 

i imagine there could be other scenarios that can trigger this "de-sync" depending on display mode, refresh rate, display type (monitor vs HMD) and so on, but i only have one PC and display to test with personally. my display is Gsync compatible and i did try fully disabling VRR in case it is a VRR-specific problem but that did not change the behavior. i also tried disabling MPO (multi-plane overlay) with no success.

 

i even did a complete wipe of my SSDs and full reinstall of windows/drivers/apps etc and the behavior is exactly the same.

 

disappointed there has been no dev response at all to this. it may be something that manifested itself due to recent Windows changes in dwm management etc, but i'm sure it could be fixed on the devs' side.

 

btw, i did manage a solution using Special K (the tool i mentioned above) but it was not the process i outlined before. instead i can enable the "continue rendering" feature in Special K which disables IL-2's alt-tab 10 fps framerate limiter, and this prevents the "de-sync" stutter problem 100% completely no matter how many times i alt-tab. that is why i believe the issue to be tied to the alt-tab fps limiter, but obviously this is something only devs can test and confirm.

Edited January 3, 2023 by GlobFly