Chasing Stuttering Red Herrings...and then Eureka!

[Tomaz Drnovsek 440]

Just now, Sethos said:

So it's both something that has been suggested for years and a placebo, interesting 🤔

Disabling fullscreen optimizations and Auto-fill main view are two different things.

[Noel 4,503]

7 minutes ago, Tomaz Drnovsek said:

I'm using unlimited/vsync but at 60Hz. I already have "Disable fullscreen optimizations" checked. Maybe it's a v5 thing?

Tomaz, unless in what you're flying and where you're flying you're able to ALWAYS maintain a frame rate of 60 you should have ample stuttering happening on a regular basis whenever you dip below 60 either from too much load on the CPU and/or GPU.  For many the addition of complex planes and scenery obviate that so even people w/ the highest end hardware will have vsync to 30 to get that ultra fluid performance.

[Boomer 1,619]

Is this "game bar" a P3D or a Windows 10 setting?

[Tomaz Drnovsek 440]

1 minute ago, Noel said:

Tomaz, unless in what you're flying and where you're flying you're able to ALWAYS maintain a frame rate of 60 you should have ample stuttering happening on a regular basis whenever you dip below 60 either from too much load on the CPU and/or GPU.  For many the addition of complex planes and scenery obviate that so even people w/ the highest end hardware will have vsync to 30 to get that ultra fluid performance.

Not with TrackIR. Using TrackIR with 30Hz is not fluid at all. 

[Sethos 4,343]

Just now, Boomer said:

Is this "game bar" a P3D or a Windows 10 setting?

Windows 10 thing, if you look in your settings panel and under "Gaming", first entry is called "Xbox Game Bar"

[Noel 4,503]

1 minute ago, Boomer said:

Is this "game bar" a P3D or a Windows 10 setting?

It's a Windows 10 thing.  Go to Settings in Windows 10, then Gaming/Games, then deselect Game Bar.  It turned out this was not influencing the stuttering issue for me, but the disabling FS optimizations in Prepar3D.exe properties has.  

[Noel 4,503]

2 minutes ago, Tomaz Drnovsek said:

Not with TrackIR. Using TrackIR with 30Hz is not fluid at all. 

I don't use TIR so can't comment on that.

[Slayer 190]

8 hours ago, Noel said:

Yes this seems to have fixed the issue in the test flight I just did in the Dash 8 in a complex scene.  I can enable auto-fill and the stuttering issue remains resolved.  This was corroborated by LM on their forum when I posted the issue there.   He also said leaving game bar enabled could also contribute to this problem for some.

We had a similar issue for a few people during testing for the MV KA350i  with the screen flashing etc, disabling that also corrects that problem.

[somiller 694]

21 hours ago, PurdueKev said:

Limiting fps that low won't work for me and disables Gsync anyway. I am running my monitor at 50Hz for P3D with Gsync enabled - my monitor is not capable of 30 Hz. If you aren't seeing these stutters in your setup in the first place, this won't have any effect.

Your monitor doesn't HAVE to support 30 Hz, it just has to use that nifty Gsync function that factors fps. In other words, if you lock at 30 and your monitor will only go down to 50Hz, gsync will produce two refresh cycles for each frame and refresh at 60Hz (30fps x 2 = 60Hz) = perfectly smooth locked 30fps.

[PurdueKev 159]

2 hours ago, somiller said:

Your monitor doesn't HAVE to support 30 Hz, it just has to use that nifty Gsync function that factors fps. In other words, if you lock at 30 and your monitor will only go down to 50Hz, gsync will produce two refresh cycles for each frame and refresh at 60Hz (30fps x 2 = 60Hz) = perfectly smooth locked 30fps.

Gsync isn't working that way on my monitor.  Locking at 30 disables the variable refresh rate adjustments because you are below the threshold, and I have had no success with half-refresh-rate vsync at fixed 60 Hz while locking frames at 30.  The scenario you painted doesn't yield "smooth" 30 fps anyway - each frame has to be duplicated to generate the extra refresh cycles (your gpu is not magically generating new unique frames twice as fast) which leads to a pronounced flickering, and if the frame timing does not match the multiplier perfectly the majority of the time you will get stutters.

Edited April 24, 2020 by PurdueKev

[somiller 694]

10 minutes ago, PurdueKev said:

Gsync isn't working that way on my monitor.  Locking at 30 disables the variable refresh rate adjustments because you are below the threshold, and I have had no success with half-refresh-rate vsync at fixed 60 Hz while locking frames at 30.  The scenario you painted doesn't yield "smooth" 30 fps anyway - each frame has to be duplicated to generate the extra refresh cycles (your gpu is not magically generating new unique frames twice as fast) which leads to a pronounced flickering, and if the frame timing does not match the multiplier perfectly the majority of the time you will get stutters.

I never said the GPU was magically generating new unique frames twice as fast...I said the monitor will refresh twice for each frame generated by the gpu. GPU outputting 30 fps; monitor refreshes each frame twice@60Hz. Sorry for you that it doesn't work on your system, but fps factoring has been a function of Gsync for at least a couple of years, so maybe you have an older Gsync monitor.

[Christopher Low 5,354]

Initial tests do not seem to indicate that disabling "Auto Fill Main View" or "Full Screen Optimisations" makes much of a difference to the stuttering issue on my PC.

[Noel 4,503]

6 hours ago, Christopher Low said:

Initial tests do not seem to indicate that disabling "Auto Fill Main View" or "Full Screen Optimisations" makes much of a difference to the stuttering issue on my PC.

Are you using UNLIMITED/vsync to 30Hz refresh?  The stuttering I get w/o disabling either of those is a kind of stutter that comes in waves about every 6-14 seconds constantly, and each event last about 1 to 1.5 seconds and that was in the context if perfectly smooth video and regardless of having major CPU/GPU headroom so it was very atypical for me.  As I say it was unlimited/vsync to 30Hz that really became the basis of glassy smooth video unless you have settings adjusted such that your CPU or GPU are getting too close to 100% then seriously poor video ensues and stays that way until you're back under 100% CPU/GPU load.  Turning while taxiing would make it more apparent sometimes.  

[Christopher Low 5,354]

My target framerate setting is Unlimited, but I have VSync disabled. My monitor is not capable of a 30Hz refresh rate, and there is no way that I can keep framerates above 30fps everywhere with the detail settings that I use in the simulator.

Edited April 24, 2020 by Christopher Low

[Ianrivaldosmith 5,317]

I can’t believe in this modern era, that people even contemplate suggesting using 30HZ or 30FPS and proclaim its smooth. It’s very well may be smooth but, it’s just headache inducing. Especially using track IR or a decent G-Sync monitor. 
The minimum hertz I’m willing  to go is 60 and that’s bad enough. Never mind ANYTHING below 30fps.