Stuttering issues but no actual framedrops?

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Vye

Stuttering issues but no actual framedrops?

Post by Vye » Sun Feb 19, 2017 22:34

So this is something I've been experiencing lately, but isn't sure if it's an actual issue or not. Basically, when running 2.3.2, I've been noticing these small stuttering issues going on during gameplay. Just randomly, the game feels like it stutters for a bit for no really discernible reason. However, it doesn't seem like I'm dropping frames, since checking it with vid_fps, it doesn't change at all, hovering around 60FPS like it should, only variance being it sometimes reads 61 or 59FPS instead.

Is this an actual problem I'm having, or is it just my mind playing tricks on me? I do use a lot of the new GZDoom features, which I understand would take up more resources to run the game, but I don't really see any difference between these odd jerkings around by turning off things like hi-res textures, resize textures and sprites, multisampling, voxels and anisotropic filtering. The game still runs smoothly for me when I've been playing wads like BTSX and The Journey with Doom Rogulike Arsenal, and even on the larger levels of things like ALT (although the ones with bigger map-sizes and larger enemy counts feel noticably less smooth, even though again, vid_fps doesn't report the FPS counter actually changing.)

Is it my hardware being inferior, running a GTX 960 with an i5 6400? This has really been bugging me lately, and I can't really see any reason for why this keeps happening.

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Rachael
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Re: Stuttering issues but no actual framedrops?

Post by Rachael » Mon Feb 20, 2017 0:20

This is a problem with dwm.exe not syncing properly with GZDoom's renderer. This will happen especially if you are using a dual-renderer setup, such as Optimus, and seems to be a fairly common problem in Windows 10. Microsoft is aware of the issue but considers it extremely low-priority.

Try putting this in the console:

Code: Select all

vid_vsync false
vid_maxfps 59
(yes, 59, not 60)

This should make the game appear a lot smoother.

This trick will make GZDoom render "off-frame" for every frame, preventing dwm.exe syncing with it - this pretty much ensures that it always gets the proper updates. I tried it by setting vid_maxfps 61, as well, but noticed this also created a noticeable stutter, but setting it to 59 seemed to get rid of that completely.
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Graf Zahl
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Re: Stuttering issues but no actual framedrops?

Post by Graf Zahl » Mon Feb 20, 2017 0:43

Infrequent stutters may also be caused by some background process stealing a bit of time on occasion. You can test this by opening the Task Manager and play windowed side by side with it. Maybe some odd thing will pop up on occasion with an unreasonably high CPU percentage.

Vye

Re: Stuttering issues but no actual framedrops?

Post by Vye » Mon Feb 20, 2017 5:16

Hello again, and thanks for the advice. I've heard that dwm on Win 10 could cause issues in games, but this is the first time I've really begun to noticing it over here.

I tried disabling vsync and capping the FPS to 59, but unfortunately, it didn't seem to do anything for me. In fact, it felt like the stutterings became MORE frequent with it turned on, although that might've just been my perception of it. I had the Task Manager open at the right-hand portion of my screen (I run the game windowed at 1440x900 resolution), but I couldn't notice anything infrequent popping up and taking up a lot of system resources. Though, I did notice that when I cap the FPS with the vid_maxfps command, it doesn't exactly stick to the FPS rate i set it on. Instead, it's shown to be 63FPS instead:

Image

I don't know whether that helps my case any or not, but it's something I noticed regardless. Never did the FPS sit at 59 for me as far as I could tell. Do I need to update my GPU drivers? I'm a few steps back and been a bit weary upgrading to the latest Nvidia driver out of fear of it causing any damage to my system's hardware.

Thanks again for the help.

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Rachael
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Re: Stuttering issues but no actual framedrops?

Post by Rachael » Mon Feb 20, 2017 9:58

About DWM: Go to the command prompt (as administrator) and type: "taskkill /f /im dwm.exe" - this often fixes dwm issues but keep in mind that sometimes it does have a chance of crashing the system (and forcing you to restart). Don't restart DWM.exe by yourself - Windows handles that automatically for you, and running a user-initiated instance will cause instability.

--

About NVidia drivers:

Ideally, your system should not go poot if you upgrade the drivers. That doesn't mean it always ends smoothly though. Very rarely does it damage hardware, though.

Sometimes you just have to take the risk and hope for the best. You can mitigate a lot of problems by using a driver cleaner to uninstall the old driver, and restart, before you install the new one.

Another way you can mitigate problems is to take note of your current driver version, and write it down, and install a new one, and if things do fuck up you can go back to your old version.

I wish I could tell you that upgrading your driver should be just fine - but my experience with it has never been all roses. Your mileage may vary.
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Re: Stuttering issues but no actual framedrops?

Post by dpJudas » Mon Feb 20, 2017 18:51

What frame rate are you getting when vsync is off and maxfps is set to zero? If the number is close to 60 fps, you might want to try lower the OpenGL settings a bit so that GZDoom gets a little more headroom.

For example, I run GZDoom at only 4x MSAA and medium quality SSAO instead of 16x MSAA and high quality SSAO. This is because with the two things at max my frame rate is only hovering slightly above 60 fps (around 80 fps as far as I remember), which can produce some occasional microstutters. I still play with vsync on, just without maxing out the GPU fully.

Vye

Re: Stuttering issues but no actual framedrops?

Post by Vye » Tue Feb 21, 2017 0:18

It didn't seem to do anything for me when I tried it. I put in the command in the command prompt, screen blacked out for a bit, and then it said it had successfully terminated dwm.exe. I then tried playing the game again, but I couldn't see any noticeable improvement. :( The screen still appeared jittery to me like before, FPS was still capped to 63. It's nice to know that the issue doesn't seem to lie with my hardware, and it's dwm that's the culprit for this, but it's still a bit annoying i can't seem to get a fix for it.

@dpJudas with the settings I had before, I seemed to hit over 300 FPS, with the counter going around 250-300 FPS. turning on both SSAO and supersampling up high made it much lower, with 120 or so. I now tweaked my settings to have 8x multisampling and medium SSAO, the FPS going a bit over 200 or so.

I should mention that this does make the GPU spring up in heat quite a bit, around 60c pretty quickly, which I'm not sure if it would contribute any to my jittery performance? The game did seem a hell of a lot smoother with uncapped FPS than with capping it at 59 like Rachael suggested, too (obviously I'm not gonna run the game uncapped though). I didn't really notice any difference in jittery performance turning down these resource-intensive actions, either, because it seems that my system should handle it fairly okay with a lot of leeway. Should I do some other testing?

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Re: Stuttering issues but no actual framedrops?

Post by Rachael » Tue Feb 21, 2017 5:24

Well you have two options really...

First is run in fullscreen - DWM.exe will not interfere with a fullscreen application.

Second, you can either dual-boot a lower version of Windows that doesn't have dwm.exe locked on (probably not an option) or find some way to run with dwm.exe disabled (extreme system instability >_<).
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Re: Stuttering issues but no actual framedrops?

Post by Graf Zahl » Wed Feb 22, 2017 0:42

What makes you sure it's DWM and not some badly behaved service that has spikes in its CPU usage?

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Rachael
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Re: Stuttering issues but no actual framedrops?

Post by Rachael » Wed Feb 22, 2017 5:26

I guess we'll find out when he tries to run it fullscreen, won't we?
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Vye

Re: Stuttering issues but no actual framedrops?

Post by Vye » Sun Feb 26, 2017 1:10

Sorry. I have been busy over here, so I haven't had the time to test the game in fullscreen yet. I'll report back whenever I'm able to do so.

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