How are you limiting your frame rate?

[Nemo 1,145]

1 hour ago, Ted Striker said:

My life under the rock has been solid, fluid, and smooth for years...

Ted

I'm back to the internal limiter. In my case with internal limit @ 30 fps it is much more fluid than with NVCP. Even when I don't reach 30 fps with the internal limiter it is smoother than "constant" 30 fps by NVCP because in my case NVCP produces stutters and pauses and needs more VRam.

[Noel 3,470]

2 hours ago, Nemo said:

I'm back to the internal limiter. In my case with internal limit @ 30 fps it is much more fluid than with NVCP. Even when I don't reach 30 fps with the internal limiter it is smoother than "constant" 30 fps by NVCP because in my case NVCP produces stutters and pauses and needs more VRam.

Liquid smooth RTSS scanline sync 60Hz/2.  NVCP produced wretched stutters for me and both RTSS and vsync to 30Hz produce fluid  stutter-free video.

[Noel 3,470]

9 hours ago, Ted Striker said:

My life under the rock has been solid, fluid, and smooth for years...

Ted

Maybe I should have a look under the rock again eh?

Well, this belief came from the days of FSX and it applied right on up at last thru P3D 3.4.  For years in FSX I used the internal limiter and the results were okay enough to live with it assuming it was as good as it could get given the hardware and sim.  Then one day I noticed in a particularly complex scene if I set the sim up with a frame rate limit internally of 30, I would only get 23-24, but if I switched to unlimited, I was getting 30 or more.  From there I thought an external limiter might be a way to capture the better frame rate, because for certain a frame rate of 23-4 even if the frames intervals are equal, isn't going to have a very fluid appearance.  I managed to find something on a gamer site that worked quite well but I don't recall its name now and it was new to the FS community.  It was a contribution I felt responsible for even though I didn't produce the applet.

This same reality happened w/ P3D up to 3.4 and on 4 different PCs.   The internal limiter clamps total performance in the end, and always did as I say.  Maybe it's changed now w/ better hardware, meaning the hardware is sufficient to overcome the penalty incurred w/ the internal limiter.   I admit it I haven't tried it since installing P3D 4.5.  When I finally discovered vsync>30Hz screen 5y ago that was the end of less than excellent fluid video and that logic applies to both the former last PC and my current recently built one.  Hence, I'm a staunch proponent that any method that allows one to stay unlimited in-sim yet limit frames has the best potential to yield consistently best results.   For some reason NvCP's limiter created stutters, not so w/ RTSS scan line.   After flying 4 or 5 flights using RTSS scanline to a 60Hz screen while quite good in terms of fluidity in the end vsync>30hz screen seems best, and that mainly because the main thread is not hammered on unless...it is.  That is, reported % load is commensurate w/ the context, whereas w/ RTSS it's always near or at 100%.

[mrlip 33]

10 hours ago, Noel said:

Liquid smooth RTSS scanline sync 60Hz/2.  NVCP produced wretched stutters for me and both RTSS and vsync to 30Hz produce fluid  stutter-free video.

Hi Noel, I haven’t used RTSS before. Currently using NCP to limit FPS to 30. I have a 60HZ screen and run unlimited in P3D V5. Could you give a quick run through as to how RTSS and P3D should be setup? Does RTSS take priority over NCP profiles?

[ShezA 176]

1. In-sim: disable vsync, change to unlimited frames
2. start MSI afterburner, RTSS starts automatically, both are minimised in tray
3. RTSS: bottom left press Add, find your prepar3d exe and add. Prepar3d is now added to list in RTSS
4. RTSS: click on the added prepar3d in list, on right is scanline sync, click the word itself and you will cycle through the options, use X/2, on right click down arrow to get -1

That is the basic limit RTSS set. MSI AB and RTSS have to run every time when you run P3D or you will may get artefacts.

If you need to get the on-screen parameters let us know.

[Noel 3,470]

7 hours ago, mrlip said:

Hi Noel, I haven’t used RTSS before. Currently using NCP to limit FPS to 30. I have a 60HZ screen and run unlimited in P3D V5. Could you give a quick run through as to how RTSS and P3D should be setup? Does RTSS take priority over NCP profiles?

In addition to Shez' outline a couple of other things to get right:

1.  Be sure to turn the frame limiter in NCP off.

2.  In RTSS hit the Settings button, and on the General tab, select Enable framerate limiter.  You won't set a value (of 30, for example) anywhere because when set up like this scan line sync becomes the method to get to 30fps instead of using vsync in-sim, so yes turn OFF vsync in-sim, but keep unlimited on in-sim.  You can see I have Scanline sync x/2, where x is entered as '60' to the right, for your screen's refresh rate.  I thought that is what this entry was for, but I guess it's not and has to do w/ a scanline offset or something, the '60'.  It doesn't seem to matter where I put that but it doesn't hurt it to leave it at 60 FWIW.  Here's what I see when it is setup correctly--to the right is what pops up when you hit the settings button in RTSS:

 

If your screen can do 30Hz and you haven't tried it, do.  Both work the same to provide smooth stutter-free performance, but w/ direct vsync to a 30Hz screen the CPU core dedicated to P3D's main thread will vary according to demand, whereas w/ RTSS scanline sync that core stays close to or at 100% which isn't all bad, but unnecessarily makes the main thread work harder to get the same result.

Edited May 31, 2020 by Noel

[Ted Striker 324]

11 hours ago, Noel said:

Then one day I noticed in a particularly complex scene if I set the sim up with a frame rate limit internally of 30, I would only get 23-24, but if I switched to unlimited, I was getting 30 or more.

My experience is the same if my settings are too high and the unlimited frame rate without vsync is close to 30. My computer is long overdue for a replacement and I am using a 4k monitor so I really have to be conservative with my settings. I misread or my old mind misunderstood Bert's comment. I thought he was referring to using external additional tools. I generally don't use the P3D internally limited framerate but have been using the P3D's vsync at 30 hz only for years. My sim is smooth with the internal limiter as long as I have plenty of excess frame at unlimited. However, I get tearing without vsync so I use P3D's vsync instead of the internal limiter. This has been the case for me with P3Dv3 and P3Dv4. With FSX I had the best results following NickN's bible and used nvidia inspector. I am still on windows 7 so I don't have P3Dv5.

Ted

 

[ShezA 176]

1 hour ago, Noel said:

In addition to Shez' outline a couple of other things to get right:

1.  Be sure to turn the frame limiter in NCP off.

2.  In RTSS hit the Settings button, and on the General tab, select Enable framerate limiter.  You won't set a value (of 30, for example) anywhere because when set up like this scan line sync becomes the method to get to 30fps instead of using vsync in-sim, so yes turn OFF vsync in-sim, but keep unlimited on in-sim.  You can see I have Scanline sync x/2, where x is entered as '60' to the right, for your screen's refresh rate.  I thought that is what this entry was for, but I guess it's not and has to do w/ a scanline offset or something, the '60'.  It doesn't seem to matter where I put that but it doesn't hurt it to leave it at 60 FWIW.  Here's what I see when it is setup correctly--to the right is what pops up when you hit the settings button in RTSS:

 

If your screen can do 30Hz and you haven't tried it, do.  Both work the same to provide smooth stutter-free performance, but w/ direct vsync to a 30Hz screen the CPU core dedicated to P3D's main thread will vary according to demand, whereas w/ RTSS scanline sync that core stays close to or at 100% which isn't all bad, but unnecessarily makes the main thread work harder to get the same result.

Is this '60' a new entry? I thought -1 was what you were using?

[mrlip 33]

5 hours ago, ShezA said:

1. In-sim: disable vsync, change to unlimited frames
2. start MSI afterburner, RTSS starts automatically, both are minimised in tray
3. RTSS: bottom left press Add, find your prepar3d exe and add. Prepar3d is now added to list in RTSS
4. RTSS: click on the added prepar3d in list, on right is scanline sync, click the word itself and you will cycle through the options, use X/2, on right click down arrow to get -1

That is the basic limit RTSS set. MSI AB and RTSS have to run every time when you run P3D or you will may get artefacts.

If you need to get the on-screen parameters let us know.

 

2 hours ago, Noel said:

In addition to Shez' outline a couple of other things to get right:

1.  Be sure to turn the frame limiter in NCP off.

2.  In RTSS hit the Settings button, and on the General tab, select Enable framerate limiter.  You won't set a value (of 30, for example) anywhere because when set up like this scan line sync becomes the method to get to 30fps instead of using vsync in-sim, so yes turn OFF vsync in-sim, but keep unlimited on in-sim.  You can see I have Scanline sync x/2, where x is entered as '60' to the right, for your screen's refresh rate.  I thought that is what this entry was for, but I guess it's not and has to do w/ a scanline offset or something, the '60'.  It doesn't seem to matter where I put that but it doesn't hurt it to leave it at 60 FWIW.  Here's what I see when it is setup correctly--to the right is what pops up when you hit the settings button in RTSS:

 

If your screen can do 30Hz and you haven't tried it, do.  Both work the same to provide smooth stutter-free performance, but w/ direct vsync to a 30Hz screen the CPU core dedicated to P3D's main thread will vary according to demand, whereas w/ RTSS scanline sync that core stays close to or at 100% which isn't all bad, but unnecessarily makes the main thread work harder to get the same result.

Thanks both for your help, I've set that up so will give it a go next flight!

[bbuckley 113]

3 hours ago, ShezA said:

Is this '60' a new entry? I thought -1 was what you were using?

I use the -1. The parameter there tells RTSS where to put the tearline. A 2160P monitor has additional lines per displayed frame to provide a buffer before loop back to the top. Setting a negative number tells it to put the tearline that number of lines below the last line in the displayed resolution, so off screen (unless the negative number is larger than the buffer in which case it loops back up). In @Noel's example of 60 it should put the tearline 60 lines down from the top. But in P3D I don't really see a tearline in any event. I believe that is due to the relatively low dynamic movement in the scene compared to some action games, but not sure.

Edited May 31, 2020 by bbuckley
typo

[Mischung 48]

Hi!

It took some time, but because I started this poll I wanted to come back on this topic now 🙂

First off all, thank you very much for voting and the great discussion! (until now 196 members took part!) 👍

I know that this poll was not as complete as many suggested, but I think it revealed the most basic settings we're using in our sim right now.
I'm aware this all depends on the P3D-version you are using and your monitor refresh rate and so forth...but I did not want to bloat up this poll.

I've seen a lot of different settings people are using and of course every system is different, with various addons and hardware, but I think I identified four major configurations which are used very often.

They can be split into two groups:

1) Monitor refresh rate < 60Hz (or monitors with any other sync-feature)
If you're lucky and your monitor supports it, you can set the refresh rate to 30Hz or even lower and then use VSYNC to match the fps to the monitor's refresh rate.

2) Monitor refresh rate >= 60Hz
I would guess the majority does not have the ability to set their refresh rate to 30Hz or below, so in that case there are three major configuration I've seen:

a) Use the P3D internal-frame-limiter
A lot of people are using the internal limiter (~31%).
Also a lot of other people said it's rubbish and did not understand why it is used at all.
So I must admit I've used the internal limiter for quite a long time too, until it did not satisfy me anymore.

b) Use the NVidia-frame-limiter
Another 25% are using the NVidia Limiter. Wether via NV Control panel or via NV Inspector.
I have not used it yet, but planned to try it, but more on that later.

c) Use RTSS with the scanline x/2 option
This tool seems to be a bit undervalued, because at the moment only <5% are using it to limit their frames.
I've been using this tool for some time now. For me the option "scanline sync x/2 = -1" was performing quite well.

I'm sorry, but this is going to be a bit longer 😂 🙈

With these options in mind I wanted to do a comparison to find out, which configuration works best.
For a real comparison however, you need a measured value to be able to quantify the differences.
For that purpose I used a tool called "CapFrameX", which is absolutely great for measuring frame times.

So this was my test setup:

System-specs:
Intel i7-9700K @4.9GHz
NVIDIA RTX 2080 8GB (Palit Super Jetstream)
32GB RAM @3200MHz
2x M.2 SSD Samsung EVO 970 (OS + Sim)
Three Full-HD monitors using Nvidia-Surround @60Hz (only 60Hz available)

OS and NVidia-driver
- NVIDIA driver 446.14
- Windows 10 - 64Bit - 1909 - Build 18363.836

P3DV5 - HF1 (with only selected addons)
    - ORBX Global Base/OpenLC NA/Building/TerraFlora2
    - FS Global Mesh 2010
    - ChasePlane
    - ENVTEX/ENVSOUND/ENVSHADE
    - FSUIPC
I also tried with all addons disabled, but the results differ not that much.

P3D-Settings
 - no AM in use (using all 8 cores - 8 full cores, no HT for the 9700K)
 - my settings are very reasonable and not every slider right (maybe I add them later, but I recognized they did not play a major role regarding fps - as long the system is not overloaded of course)
 - No cfg-tweaks in place
 - Absolutely no traffic
 - Weather: only Clear Skies
 - Using a Standard Aircraft - Mooney Acclaim
 
I recorded a flight in P3D, so I could load this recording and use the exact same flight for all captures.
Taking off @KFUL, flying some circles and then landing @KLAX (around 13min flight time)

As I only have monitors with 60Hz, I had to focus on the second group 2) with config a), b) and c) mentioned above.
I tried a lot of different settings and variations, so I will pick the most representative for evaluation.

Here are some basic findings:
- There are always some little stutters, which I could not get rid of.
  Even with disabled addons and all sliders left they are still there, no matter which configuration I tried.
  It's not happening every second, but appr. 6-7 times during the 13min flight. (remember it was LA I was flying over)
- CPU (Core0) load varies depending on the configuration (RTSS is always @100%, where an external limit with NVCP was around 50-60%)
  I've read about the behavior using RTSS (using up the idle cycles) and it does not seem to harm, so I accepted this behavior as is.
- I also tried the AM-trick (removing core 0 and then set it again using task-manager) -> it seems to spread the load better, but regarding frame times it made absolutely no difference at all (snake oil...ha ha)
- VSYNC and Triple Buffer on or off also makes not much of a difference for my setup, but I guess, that's because of the 60Hz refresh rate.
  
And here is the table for 5 different configurations - using the standard deviation for comparison:

So when looking at the standard deviation of the FPS, the configurations using RTSS are definitely recommended.
I tried different combinations with unlimited internal, using the P3D limiter@33 and the combined option with the RTSS limiter @24fps (no big difference).
Interesting is, that the NVCP-limiter is even worse compared to the internal limiter.

And here come the diagrams (showing FPS during the 13min test flight):

Here we can see, that the NVCP-limiter has much more fluctuations compared to the internal limiter.
Also visible are the occuring stutters, because they are always at the exact same position (causing long frames with 6-15fps)
I would guess, this is some kind of loading issue during the flight (maybe an airport coming into range).

Looking at these results I would definitely recommend using RTSS with the "scanline sync x/2 = -1" option for users with a 60Hz monitor (limiting internally or not has to be tested, but it's no a big difference...maybe autogen is loading better with limiting in sim).

The NVCP-Limiter is not doing a great job, so I would rather stick with the internal limiter in this case 😜

Cheers!

Marc

[Bert Pieke 6,521]

Unless you like reducing CPU Core0 load, in which case the NCP limiter becomes an attractive option 😉

[Mischung 48]

6 hours ago, Bert Pieke said:

Unless you like reducing CPU Core0 load, in which case the NCP limiter becomes an attractive option 😉

Hi Bert,

that's what I thought at first too, but there seems to be an easy explanation 😉

Using the NVCP limiter wll show your "real" CPU usage/load, so you can use it to check your settings.
In my case the CPU was between 40-60%, so this should be fine.

But the results with RTSS are much better regarding fluctuations and all methods have the same loading stutters at the same position in flight.
So even the CPU usage goes up to 100% it does not harm at all and here is why:

RTSS is limiting the frame rate by introducing wait cycles to the rendering task (usually core 0). These wait cycles will be shown in task-manager as CPU-load, but it is not real (also worth reading Link). I would assume it will also not change CPU-temperatures etc, but I will check that again in the sim 🤓

This method seems to be the best way to realize a very stable frame limiting, but one cannot see the "real" CPU-usage now.

I would use the NVCP-limiter to find out the best P3D-settings not overloading your CPU and afterwards use RTSS for daily use 🙂

Edited June 1, 2020 by Mischung
Rendering task instead of CPU

[kaha 205]

Everything said here also applies to V5? Or are you talking V4 only? I still extenally limit fps in V5, so I wonder if I'd better get rid of it?

 

Karl

[Noel 3,470]

5 hours ago, Mischung said:

This method seems to be the best way to realize a very stable frame limiting, but one cannot see the "real" CPU-usage now.

I would use the NVCP-limiter to find out the best P3D-settings not overloading your CPU and afterwards use RTSS for daily use 🙂

Good job Marc!  It is in complete agreement w/ my anecdotal experience.  Unfortunately you were not able to compare vsync to a 30Hz screen which solves the one limitation of RTSS which you mention above, and realtime performance is at least as good as RTSS scanline, and fortunately that option exists for those who don't happen to have a 30Hz capable screen.  

Hopefully your 'study' will get people using this fabulous way to create ultra smooth flight.  I initially thought the main core thread wasn't running warmer using RTSS compared to vsync to 30Hz but I'm prettty sure that is not sure that's the case because you can't rely on the reported core temp to evaluate this if you're using a fan profile to modulate fan speed by core temp.  What I find is my fans are spinning much faster using RTSS than w/ vsync to 30Hz.