10 minutes ago, bbuckley said:

Hi my friend @DaveCT2003, I absolutely believe you on this but intuitively I don't understand the issue if your FPS exceeds the "real time FPS of 29.97". I can intuitively see how a slower FPS would cause sim calculations to need to slow down the physics to match the scene, but why doesn't a higher FPS just mean the sim essentially displays nearly the same scene in consecutive frames but the physics remains at real time? Is there a paper or something I can read to understand?

Actually, ther is a paper on this!  Strange you should ask!  I'm pretty sure I saved the paper I found on this, but it's been years and since I'm in the flight sim business I have many, many hard drives crammed with such information.  But I'll try and find it.

How did I first notice this?  For that, I'd have to tell you that a heavy percentage of flight simmers significantly limit their enjoyment of our hobby - and that's just a cold hard fact - by flying alone. Yeah, some fly online, but that's still flying alone.   Since 1996 I've been flying with others, including group flights and shared cockpit flights (where we are actually talking, working, coordinating, joking, etc. etc. etc.) together where most flight simmers (even the online guys) it's still just them and their computer.  Anyway... we coordinate ground speed so that we can maintain our intervals and that's how I came to notice this.  It's just that easy and simple.

So I started digging into this, and in fact I did find a paper on it.  As memory serves I found the paper sometime around 2008 and I'm fairly sure it's on one of my hard drives.  I have a very busy weekend, but I'll try to look for it next week and I'll happily send it  your way if I find it.  The basis of the paper was Time in simulations.  You know, I may have very well posted this here on AVSIM back between 2008 and say 2010 as well.  I remember engaging in a dialog about this.

But seeing this for yourself is too easy.... just get someone online with you and fly as I described... in FSX/P3D by the way, I have no idea how this works with Xplane.

 

Actually, you don't even need to fly online with someone to see this.  Just get an accuarate time reference, make a 3 hour flight in your sim at say 60fps, and then repeat the flight at 30fps.

This problem used to be well known in our community and it's one the reasons that tools like FS Real Time, FS Time Sync and Chrono Timer exist.

 

 

I’ll give it a try. I did try a search for info using key words but obviously not the right ones...

4 minutes ago, bbuckley said:

I’ll give it a try. I did try a search for info using key words but obviously not the right ones...

I had a few minutes, so I did a Google search for "flight simulation elapsed time problem: and one of the first hits was the one below.  So, now we know that Xplane also suffers from this issue.  I assumed so, but didn't want to say it. Laminar is kind enough to give a me a copy of XPlane each time there is a new revision but I still haven't had time to use it much.

This gives me an opportunity to give a shout out to Austin and all the Laminar Research friends I had dinner with last year in Orlando - which by the way Austin didn't join us for as he was flying his aircraft down and ran into some really terrible weather!  Those who were there knew I was a P3D guy and STILL hosted me for a truly amazing dinner.  Wonderful people, each and every one of them!  In fact they are among the VERY, VERY best of people I've met and got to know in the flight sim world during these past 40 years!  That said... there sim suffers from the same issue, and maybe they can X-Plain that? (okay, bad joke, I'm still working on my second cup of coffee.... LOL!).

https://www.x-plane.com/kb/the-simulators-measurement-of-time-is-slow/

 

Anyway, this issue used to be very well known in the community years ago, nice to have a chance to bring it back into focus.

 

For me the fps limiter within NCP gives me stutters, I use NVI's frame rate limiter v2 on 30 and I have my sim as smooth as you can get. The only other settings I use are: Vertical sync: 1/2 Refresh Rate, Vertical sync tears control: Adaptive, Texture filtering: High Quality and Power management mode: Prefer maximum performance. Monitor Refresh Rate 60GHz

Edited February 22, 20206 yr by SergioN

NCP limiter seemed to induce more stutters for me as well, so I dumped it and reverted back to the in-game limiter.

If you haven't done so already, you might want to try RTSS Kyle. I tried the nVidia limiter, stutter fest, and went back to RTSS with great haste. For me, 98% stutter free and as smooth as I'm going to get.

Cheers,

Mark

I was using internal "limiter" alone at 30 FPS, no other settings related to it. It's a 4k screen 60 Hz. I was definitely not happy with this, lot's of occasional stutters (or microstutters), then I tried the NVidia limiter at 30 together with Adaptative "refresh rate" - does it make sense using this kind of thing provided P3D is not a real native fullscreen application?

The internal VSync never made a difference for me neither.

The thing is, apparently the NVidia limiter seems to be a bit better now, but it can be a placebo.

On 2/21/2020 at 12:23 PM, KenG said:

Works perfectly for me. 30 fps and rock solid performance. No stuttering that was not already in the sim, i.e. Orbx SOCAL flying over LAX still hammers my system. I need the Cray Shasta for that area. 

thats been like that since fs98.

 

 

 

 

18 hours ago, DaveCT2003 said:

 

This problem used to be well known in our community and it's one the reasons that tools like FS Real Time, FS Time Sync and Chrono Timer exist.

 

 

not too mention LM couldnt be bothered to sort out the time zone bgls until very recently.  but they added some airport in saudi..

year of the simmer and all that...

Edited February 23, 20206 yr by fluffyflops

i can confirm i updated the new drivers last night. 

I have a 4k monitor which is both 60 and 30 hertz.

previously I was running it at 60hertz (no mouse lag) and then using ndvia inspector to lock frames at 30.5 and half refresh rate.  it was working like a charm, alas not any more with the new drivers its a stutter fest.

some tweaking now needed as Ive had to go back to lowering to 30 hertz with no frame limter in ndivia inspector.

Edited February 23, 20206 yr by fluffyflops

19 hours ago, DaveCT2003 said:

 

https://www.x-plane.com/kb/the-simulators-measurement-of-time-is-slow/

 

Anyway, this issue used to be very well known in the community years ago, nice to have a chance to bring it back into focus.

 

Yes. the basic problem is one not keeping consistent time. In some very old software a lap time could be smashed in a car racing game because the sim runs too slow. FSX and P3D don't care about the fps more than the consistency.

For example I set up a saved flight on AP going into a turn and on to a next waypoint. Playing back the saved game results in the plane overflying some marker. Now set up the sim so that it cannot maintain FPS and find whether that marker is overflown. The more even the flow of the sim the more likely the plane overflies the marker. Time is synced between nodes so position can vary, not time.

Also it should be noted that some forms of addon software can be a problem. I mentioned those programs running off the frame event of the sim. As the frame rate increases, the code invoked by the frame event has to run faster and faster. This goes past the point which the addon keeps up and consequences are that the two nodes become confused. Programs avoiding the frame rate event are not affected.

So when one is at 30 fps and the other at 60fps the likelihood is that the 60 will show a larger variation in fps compared to the 30fps node. Both should use the locked fps slider since frames are not limited but output at a consistent frequency so that the networked mode remains good. The Frame rate lock in the Sim Display settings allows more accuracy in the simulation.

Edited February 23, 20206 yr by SteveW

Here I still use Vsync on , but with the NV Limiter set to 1 framerate more.

That eliminates the Vsync FPS spikes.

 

1 hour ago, GSalden said:

Here I still use Vsync on , but with the NV Limiter set to 1 framerate more.

That eliminates the Vsync FPS spikes.

 

Are you running your Sony TVs at 30 Hz and also are you running with TB on and Unlimited in P3D. I run my Samsung 4K TV at native 30 Hz and use Vsync, TB  and Unlimited in P3D and found that to be smoother than the experimentation I recently did with the new Nvidia frame limiter at various settings around 30 fps. I had not thought about adding an external 31 fps limit with Nvidia CP to my current setup.

Joe

Is there a way to measure stutters in P3D to figure out which method is actually working the best? Ideally you could just record the same scenario and then compare.