FPS Seems Incorrect

[dresoccer4]

So having a strange issue that just began this week. I have a 60hz monitor and v-sync enabled so the frame rate tries to stay at 60fps.

In the sim I enable frame rate displayed in the corner. Beginning this week, it says 60fps but the sim seems to slow down to below that when over dense areas. So the fps seems to drop down to like 30-40fps however it still says 60fps.

60fps in DCS looks pretty darn smooth and that's what I'm used to. So I noticed when the sim feels to have dropped down below that. Anyone had this happen to them before? It's frusterating to not know the true frame rate so I can diagnose the issue.

[Lange_666]

Yeah i have the same feeling sometimes (however already way before the last update, even in the 1.x era) but... when i switch to other FPS measuring (FRAPS or MSI Afterburner) i get the same result.

[Hiob]

Even if I would distrust the in game fps counter, I‘d be absolutely confident that afterburner works and shows the truth.

I think it’s the speed blur effect that you get when zooming by close to the ground or panning around. 60 Hz simply isn‘t enough to keep a clear image in those sceneries. Up in the sky you simply lack points of reference.

Kind of when you drive on the highway. Trees real close zoom by in a blur, whereas trees far away are almost stationary.

Another thing may be, that you get more micro stutters. 60 fps is an average in after all. Doesn’t mean that every frame is the same length.

Just a few thoughts. I don’t know obviously!

[Taz1004]

Check frametime instead of frame rate.

[dresoccer4]

11 minutes ago, Taz1004 said:

Check frametime instead of frame rate.

what am I looking for with frametime

[Taz1004]

1 hour ago, dresoccer4 said:

what am I looking for with frametime

That it is consistent.  You can google frametime vs frame rate.  But basically, you can have 60 frames in a second but if they're not displaying those 60 frames evenly within that 1 second, you will get stutter.  For 60fps, 16ms is ideal frametime.

This is mine for example.  It spiked here and there when I was moving my head around but for most part, stayed around 17ms for 60fps.

Edited December 29, 2021 by Taz1004

[dresoccer4]

20 hours ago, Taz1004 said:

That it is consistent.  You can google frametime vs frame rate.  But basically, you can have 60 frames in a second but if they're not displaying those 60 frames evenly within that 1 second, you will get stutter.  For 60fps, 16ms is ideal frametime.

This is mine for example.  It spiked here and there when I was moving my head around but for most part, stayed around 17ms for 60fps.

 

 

interesting. it looks like mine is saying 24ms frametime so that's pretty far from the 16 you mentioned. i wonder if that's causing the issues i'm reporting

Edited December 30, 2021 by dresoccer4

[Taz1004]

18 minutes ago, dresoccer4 said:

interesting. it looks like mine is saying 24ms frametime so that's pretty far from the 16 you mentioned. i wonder if that's causing the issues i'm reporting

 

I would think so.  1/60 = 0.0167.  Meaning each frame needs to be on screen for 16.7ms.  24ms is closer to 41fps.  If the game's saying 60fps but feels like 30-40fps as you said in your original post, then the game may be duplicating frames to keep up with 60fps which would cause stutter.

As a test, I would try forcing FPS to 40fps or lower to see if you get smooth consistent motion at least.

Edited December 30, 2021 by Taz1004

[dresoccer4]

26 minutes ago, Taz1004 said:

I would think so.  1/60 = 0.0167.  Meaning each frame needs to be on screen for 16.7ms.  24ms is closer to 41fps.  If the game's saying 60fps but feels like 30-40fps as you said in your original post, then the game may be duplicating frames to keep up with 60fps which would cause stutter.

As a test, I would try forcing FPS to 40fps or lower to see if you get smooth consistent motion at least.

 

how does one go about forcing a lower fps in dcs?

[Taz1004]

1 minute ago, dresoccer4 said:

how does one go about forcing a lower fps in dcs?

You can do it in nVidia control panel or via autoexec.cfg

options.graphics.maxfps = 30

[dresoccer4]

15 minutes ago, Taz1004 said:

You can do it in nVidia control panel or via autoexec.cfg

options.graphics.maxfps = 30

ok i limited via nvidia control panel to 40fps. Looks like Frametime is 25ms

 

[Taz1004]

Just now, dresoccer4 said:

ok i limited via nvidia control panel to 40fps. Looks like Frametime is 25ms

 

But is it smooth or are you getting stutter?  I suggest getting benchmarking tool to check frametime like AfterBurner.

[dresoccer4]

13 minutes ago, Taz1004 said:

But is it smooth or are you getting stutter?  I suggest getting benchmarking tool to check frametime like AfterBurner.

ok so i was checking these values out more and noticed somtimes if i took a screenshot it would say 24ms and sometimes it would say 16ms, while all the while reporting it was running at 60fps. Even when locked to 40fps this would happen. 

So I took a short video to show what I now see if it looking like it flips from 16ms to 24ms back and forth. I wonder if this is 1) normal for other people and 2) if this is what's causing the perceived fps drops in my sim?

https://streamable.com/bqjnmz

[jumphigh]

17 hours ago, dresoccer4 said:

So I took a short video to show what I now see if it looking like it flips from 16ms to 24ms back and forth. I wonder if this is 1) normal for other people and 2) if this is what's causing the perceived fps drops in my sim?

Ask yourself: How do you evenly distribute 40 frames on 60 frames of the monitor? Nobody can do that! So when running a 60-Hz-monitor with V-Sync you can have 60 frames or 30 frames of the same length, nothing between. You need a new monitor supporting variable refresh rates (VRR, Adaptive Sync), e.g. a FreeSync (AMD) or G-Sync (nVidia) model. Most of them support rates as low as 40Hz (40 FPS). Some decent Samsung TVs have a range of 20Hz up to 120Hz.

Edited December 31, 2021 by jumphigh

[dresoccer4]

12 hours ago, jumphigh said:

Ask yourself: How do you evenly distribute 40 frames on 60 frames of the monitor? Nobody can do that! So when running a 60-Hz-monitor with V-Sync you can have 60 frames or 30 frames of the same length, nothing between. You need a new monitor supporting variable refresh rates (VRR, Adaptive Sync), e.g. a FreeSync (AMD) or G-Sync (nVidia) model. Most of them support rates as low as 40Hz (40 FPS). Some decent Samsung TVs have a range of 20Hz up to 120Hz.

 

no something has changed. it's like vsync isn't working. i have a strong rig and get 100+ fps normally but use vsync to lock it to 60hz as that makes it much more smooth. so while DCS still says it's running at 60fps its like its actually being rendered at 40. again this did not used to be like this. even flying the Christen Eagle through the Nevada desert (aka the easiest flight on your hardware) still makes DCS behave in this new, unsmooth fashion. 

i'm wondering if there a way to reset all of the graphics settings as maybe theres a bug

[jumphigh]

15 hours ago, dresoccer4 said:

no something has changed.

You're probably right. I have a far inferior system, playing with a RX 570 4GB and resolution 2560x1440. I use the Huey free flight mission in the Caucasus to check my frame rates. With my settings I was able to get 50+ fps. With the advent of DCS stable version 2.7.7 something seems to be broken. I can change my graphic settings to whatever I like – the lowest is looking ridiculous and worse than a game from the 90ies – but I can't get above 40 fps anymore. It's reported already.

[silverdevil]

On 12/31/2021 at 10:18 PM, dresoccer4 said:

i'm wondering if there a way to reset all of the graphics settings as maybe theres a bug

a quick way of resetting graphics is to rename options.lua found in  \Saved Games\DCS.openbeta\Config then compare the two files. the game will recreate it on startup.

[dresoccer4]

1 hour ago, silverdevil said:

a quick way of resetting graphics is to rename options.lua found in  \Saved Games\DCS.openbeta\Config then compare the two files. the game will recreate it on startup.

thanks ill try this. ive also read somewhere deleting some folders like fxo or metashaders or something can clear things out but not sure

23 hours ago, jumphigh said:

You're probably right. I have a far inferior system, playing with a RX 570 4GB and resolution 2560x1440. I use the Huey free flight mission in the Caucasus to check my frame rates. With my settings I was able to get 50+ fps. With the advent of DCS stable version 2.7.7 something seems to be broken. I can change my graphic settings to whatever I like – the lowest is looking ridiculous and worse than a game from the 90ies – but I can't get above 40 fps anymore. It's reported already.

this is an interesting thread, thanks. yeah i'm wondering if this is the same bug i'm encountering 

[dresoccer4]

On 12/30/2021 at 3:29 PM, Taz1004 said:

But is it smooth or are you getting stutter?  I suggest getting benchmarking tool to check frametime like AfterBurner.

hey taz, did you get a chance to look at the short video i posted? i'm wondering if other folks' frametime also jumps around like that when displaying 60fps

[dresoccer4]

GUYS, I'VE SOLVED IT! For weeks now I thought maybe I was going crazy. But this evening when I booted up DCS and started a flight, it was silky smooth again, just the way I remembered it! I checked the frametimer and it was a constant 16ms, not jumping around like I posted about before. I was stunned.

I go write and email and do a couple things then go back to the sim to continue my flight when, to my horror, the terrible jaggies are back . Something had changed again. The only thing I did was alt-tab out and in. So I pull a hail mary and searech "DCS world alt tab fps issue" and lo and behold, this is a long-standing bug in DCS I found a thread back in 2018: 

Their solution was to press "left alt + enter" to have sim switch screen types (windowed, full, etc) until, like magic, the smooth 60fps screen appears. This is the magic workaround you must do if the sim doesn't like whatever is going on with your screen. I've tried this multiple times and it seems to be working every time.

I hope this helps someone else that was losing their damn mind like I was

 

[Hiob]

 

[bell_rj]

19 hours ago, dresoccer4 said:

So I pull a hail mary and searech "DCS world alt tab fps issue" and lo and behold, this is a long-standing bug in DCS I found a thread back in 2018:

The forum notified me about your post, and I'm glad to read that what I and others posted years ago has helped you!

Edited January 3, 2022 by bell_rj

[dresoccer4]

35 minutes ago, bell_rj said:

The forum notified me about your post, and I'm glad to read that what I and others posted years ago has helped you!

 

glad it helped, but sad DCS hasn't solved this long standing bug

[bell_rj]

On 1/3/2022 at 9:40 PM, dresoccer4 said:

glad it helped, but sad DCS hasn't solved this long standing bug

Well the strange thing is, some (considerable) time after I originally posted about it the bug stopped happening for me. I can't say why. Maybe it was a change in game or Nvidia control panel setting. I've also changed graphics card since then.

[Hiob]

DCS doesn't like it when other programs run (or do something) during startup. Not going into fullscreen is the exact symptom.

Just make sure, all other programs are fully loaded and in idle whilst starting DCS (e.g. TrackIR, Discord, Afterburner and so on). So in other words - no multitasking. Same while running DCS and alt-tabbing out. Chances are, you are not in fullscreen on return. If you can, use the g-sync indicator to help identify true fullscreen.