Refresh rates / stutters etc.

[BWBriscoe 116]

Hey...

I'd like some advice on refresh rates to smooth out performance in P3D5.

I'm using a Samsung 32" UJ592 4K monitor set to 3840 x 2160 with a refresh rate of 60Hz
My graphics card is GeForce RTX 2080 Ti (11GB)

I currently have P3D frame rates set to unlimited
VSync is off in P3D (and in Global settings of Nvidia Control Panel)
Variable Refresh rate is also set to off

Is there anything I should be doing to smooth out some of the stutters?
Should VSync be on in game or in Nvidia control panel (I read that it can sometimes lead to a CTD)?
Should I have Variable Refresh Rate on?

Any advice very gratefully received.

Thanks,

Ben

[John_Clarke 4]

Hey Ben,

I had the same issue with you in regards to stutters - same monitor as you. Found a way (which works well for me). 

Keep your P3D settings as you've stated. In Nvidia control panel, try this and see if it's any smoother:

Max frame rate - 33FPS
OpenGL - Your GPU
Power - prefer max performance
Threaded Optimisation - On
Triple buffering - On
Vsync - Adaptive (Half refresh)

You will only get 33fps at max but the sim works a lot smoother and I can maintain frames with no stutters.

See how you go and if it works for you.

John

[BWBriscoe 116]

42 minutes ago, John_Clarke said:

Hey Ben,

I had the same issue with you in regards to stutters - same monitor as you. Found a way (which works well for me). 

Keep your P3D settings as you've stated. In Nvidia control panel, try this and see if it's any smoother:

Max frame rate - 33FPS
OpenGL - Your GPU
Power - prefer max performance
Threaded Optimisation - On
Triple buffering - On
Vsync - Adaptive (Half refresh)

You will only get 33fps at max but the sim works a lot smoother and I can maintain frames with no stutters.

See how you go and if it works for you.

John

Thanks John, I'll give these settings a go.

Ben

[Noel 4,486]

Ben, open nV Control Panel and see if you can choose 30Hz as a screen refresh rate.  I have a Dell 3415W, curved 3440x1440 display, and it can do 30Hz.  Ever since I learned about this, after years and years of trying to improve things in P3D, I've not gone back.  You will leave frames UNLIMITED in P3D, set vsync to ON in sim, and leave all NV Control Panel set to Global (ie, don't use its built-in P3D set).  If you can do this, then setup P3D so that you NEVER see your GPU hit above 95% utilization or so, and also set your scenery sliders such that the main thread doesn't get to 100%.

This approach does two things:

1.  Assures liquid smooth, stutter-free video, overall.  I say that because P3D loads big terrain tiles regularly in complex scenery and you will always see at least the mainthread briefly hit 100%, but most often as set like this you won't see a stutter.

2.  Both you CPU and GPU are only ever going to be asked to deliver 30fps.  Because of this you can easily observe CPU and GPU load with something like MSI Afterburner w/ RTSS' on screen display.  When you done vsync to 30Hz you will see the CPU pegged almost always, and same same for the GPU.

I hope your screen will do 30Hz.  In the spec sheet on my Dell it does not state it can do 30Hz, but as I say w/ nV Control Panel it's an option.  There are a few who haven't seen it yet will tell you you absolutely need 60hz minimum refresh, but many others here and some w/ the highest end hardware possible use the vsync to 30Hz because overall it's superior at delivering fluid, stutter-free performance.  I've even set up the sim to vsync to 60Hz in an area w/o complex scenery in an easy to process plane (Majestic Q400 is about like default planes) and still, for reasons I don't appreciate, vsync to 30Hz was superior in all ways, including panning in the cockpit.

[Luis Hernandez 566]

4 hours ago, John_Clarke said:

Keep your P3D settings as you've stated. In Nvidia control panel, try this and see if it's any smoother:

Max frame rate - 33FPS

In case you can´t set your refresh rate to 30 Hz, set this max frame rate to 30 FPS instead, and VSync ON.

[Noel 4,486]

2 hours ago, Luis Hernandez said:

In case you can´t set your refresh rate to 30 Hz, set this max frame rate to 30 FPS instead, and VSync ON.

Intersting, how does that work?  VSync syncs to the monitor's refresh rate, whereas setting max frame rate to 30 FPS does not sync to the monitor's frame rate.

Others who don't have a 30Hz capable screen will use RiveTunerStatisticsServer's 'scanline sync' option, and use a divisor of 2 if they monitor is running at 60Hz refresh rate.  In that instance the get the same vsync to 30Hz thru a different method.  The only (modest) downside is the sim will still try to generate as many frames as it can, even though it only needs 30fps.   I like having headroom that vsync to 30Hz hardware affords, though I may be overstating its value.  

Here's what I mean by headroom.  The first shot is from a point in MSFS running all sliders at ULTRA, but this was running with the monitor at 60Hz, w/o vsync, and unlimited, so running as fast as it can under these settings.  Notice CPU16 at the bottom is running at 52% of maximum (CPU16 is the main thread in MSFS for my hyperthreaded i9-9900K), and the GPU is running near 100%.  41fps.

Now here is the same point in the flight, this time vsync to 30Hz screen.  Notice CPU16 is now down to 27% of maximum nearly half, and the GPU at 76%, and frame rate of course locked at 30 by vsync.  Performance, characterized by fluid, stutter-free rendering is far superior in the latter.   The CPU is even running a bit cooler.

[BWBriscoe 116]

3 hours ago, Noel said:

Ben, open nV Control Panel and see if you can choose 30Hz as a screen refresh rate.  I have a Dell 3415W, curved 3440x1440 display, and it can do 30Hz.  Ever since I learned about this, after years and years of trying to improve things in P3D, I've not gone back.  You will leave frames UNLIMITED in P3D, set vsync to ON in sim, and leave all NV Control Panel set to Global (ie, don't use its built-in P3D set).  If you can do this, then setup P3D so that you NEVER see your GPU hit above 95% utilization or so, and also set your scenery sliders such that the main thread doesn't get to 100%.

This approach does two things:

1.  Assures liquid smooth, stutter-free video, overall.  I say that because P3D loads big terrain tiles regularly in complex scenery and you will always see at least the mainthread briefly hit 100%, but most often as set like this you won't see a stutter.

2.  Both you CPU and GPU are only ever going to be asked to deliver 30fps.  Because of this you can easily observe CPU and GPU load with something like MSI Afterburner w/ RTSS' on screen display.  When you done vsync to 30Hz you will see the CPU pegged almost always, and same same for the GPU.

I hope your screen will do 30Hz.  In the spec sheet on my Dell it does not state it can do 30Hz, but as I say w/ nV Control Panel it's an option.  There are a few who haven't seen it yet will tell you you absolutely need 60hz minimum refresh, but many others here and some w/ the highest end hardware possible use the vsync to 30Hz because overall it's superior at delivering fluid, stutter-free performance.  I've even set up the sim to vsync to 60Hz in an area w/o complex scenery in an easy to process plane (Majestic Q400 is about like default planes) and still, for reasons I don't appreciate, vsync to 30Hz was superior in all ways, including panning in the cockpit.

Thanks Noel. Is this in addition to what was recommended by John above or an alternative?

Ben

[John_Clarke 4]

22 minutes ago, BWBriscoe said:

Thanks Noel. Is this in addition to what was recommended by John above or an alternative?

Ben

It basically does the same thing. I found that when I set my 4k monitor to 30HZ, I got major mouse lag as don't have a 4k enabled mouse. 

I tried what Noel did but personally found that moving around the cockpit using chaseplane as my camera system very sluggish. The reason I set 33 is to give a 10 percent buffer - I found the same fps when I set my monitor to 30Hz so wasn't any different.

I use argus monitor to check temps and utilisation and found a drastic drop in both GPU and CPU temps. I have my sliders pretty high and use a night lighting system which can drain CPU even during the day but can still maintain good performance.

Try each way and see what works for you. I'd love to see the amount of times that P3D has been started and quit just for testing purposes!

Let us know which one works best for you.

[BWBriscoe 116]

Thanks guys, really appreciate it

[Luis Hernandez 566]

2 hours ago, Noel said:

Intersting, how does that work?  VSync syncs to the monitor's refresh rate, whereas setting max frame rate to 30 FPS does not sync to the monitor's frame rate.

I use VSync just to align frame times. Framerate limiting is a side effect (and people using 30 Hz monitors take advantage of this). If I don't do so, I get tearing when panning in the VC... despite being way below 60 FPS. I hope I'm doing something wrong with this (VSync=ON at 30 FPS@NCP and 60 Hz) and I hope there's a better way to get smooth 30 FPS while keeping the 60 Hz refresh rate.

 

2 hours ago, Noel said:

Others who don't have a 30Hz capable screen will use RiveTunerStatisticsServer's 'scanline sync' option, and use a divisor of 2 if they monitor is running at 60Hz refresh rate.  In that instance the get the same vsync to 30Hz thru a different method.  The only (modest) downside is the sim will still try to generate as many frames as it can, even though it only needs 30fps.   I like having headroom that vsync to 30Hz hardware affords, though I may be overstating its value.  

I used to apply RTSS Scanline X/2, but in my laptop P3D4 is even smoother with 30 FPS set in NCP. Also, both my CPU and GPU run cooler and there is no tearing. I don't know why does this happen.

Edited February 20, 2021 by Luis Hernandez

[Noel 4,486]

1 hour ago, Luis Hernandez said:

 I hope I'm doing something wrong with this (VSync=ON at 30 FPS@NCP and 60 Hz) and I hope there's a better way to get smooth 30 FPS while keeping the 60 Hz refresh rate.

I just tried John's suggestion, but in MSFS which really responds to the same setup for me as P3D does with respect to what we are talking about here.  Since there is no slider in MSFS to set 33fps, I just set the monitor at 60hz, diabled Vsync in MSFS, but set Adaptive Vsync to half refresh and it worked pretty good, I think.  I was getting subtle recurrent brief 'surges' for lack of a better word, where animation would suddenly but briefly speed up, as if it is briefly out of sync so speeds up to catch up as it were.  Try that and see what happens for you if you don't have those brief out of sync periods or whatever they are.  In between those it was fluid. I didn't test it enough and went back to 30Hz vsync as there just isn't anything wrong with it.  You have to restart MSFS between setting changes to notice the effect.   I have no significant mouse lag, but my screen is 34" wide, 1440P. 

[Deltaguy 45]

The monitor refresh rate set to 30mhz is the best solution to get rid of microstutters.  It is truly great.

[Noel 4,486]

2 hours ago, Deltaguy said:

The monitor refresh rate set to 30mhz is the best solution to get rid of microstutters.  It is truly great.

It's amazing how many contest this, but you are right it's remarkably great.

[Ray Proudfoot 8,927]

4 hours ago, Deltaguy said:

The monitor refresh rate set to 30mhz is the best solution to get rid of microstutters.  It is truly great.

As someone who was originally reluctant to try this I have been convinced it's the best solution to minimising stutters. Minimising, not eliminating as there are still brief moments of big stutters when you're around 80nm from a major airport and multiple Ai aircraft are generated. I can live with that.

Forcing 30Hz on monitors incapable of running no lower than 60Hz via a software tweak is still second best.

And why do we get stutters? Because you're asking your CPU / GPU to do something it's incapable of. Lowering the threshold from 60 to 30 removes most of that bottleneck.

[kevinfirth 1,392]

8 minutes ago, Ray Proudfoot said:

And why do we get stutters? Because you're asking your CPU / GPU to do something it's incapable of.

..and this causes a disparity between the monitor refresh rate and the numbering frames capable of being output.  Where this occurs, the time between frames as shown in the monitor is not consistent, Ie you see a stutter.