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dutton98

VSync and triple buffering!

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Hi all, 

 

So after a few weeks i was finally able to get my P3D where i wanted it to be, no blurries and good fps. Originally i had Vsync and triple buffering set to off, but i find in the cruise when the fps gets very high its almost so smooth its not smooth if you get me. After doing a few flights with Vsync and triple buffering on i have seen that these 2 settings seems to make my sim stutter more and also gives me some of those blurries i didnt want back. 

 

Is someone able to tell me why this happens?

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but i find in the cruise when the fps gets very high its almost so smooth its not smooth if you get me.

 

Actually no. ??

 

Are you Vsyncing to 60 or 30 FPS?

 

gb.

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I have 60 fps locked in Nvidea inspector 

 

But i find its odd, cause when i have vsync and triple buffering on i seem to get more stutters and also blurries. 

 

But when vsync is off and triple buffering is off, i seem to get really good crisp textures, no stutters but on like final approach the fps gets quite bad, like when vsync is on its so much smoother. 

 

I would love to be able to have both 


What im trying to say about the smooth but no smooth, when im in the cruize the fps must get so high, that when i pan around its smooth but its almost like when i pan it stops for a millisecond and stutters almost 

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Try this Harry,

 

Set the 30fps limit in NI.

 

Display Settings set Unlimited, VSync On, and Triple Buf On.

Look at the shift-z fps you should see it around 30.

 

or

 

Set the 30fps limit in NI.

Display Settings set 30fps fixed on the slider, set VSync Off and Triple Buf Off.

 

Also I recommend setting HT On and affinity with four LPs one per core.

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With my new system I use Triple Buffering with V-Sync off and I am getting incredible frame rates. I guess it works differently for each person. 

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With my new system I use Triple Buffering with V-Sync off and I am getting incredible frame rates. I guess it works differently for each person.

Yes that's true, vsync off gives the most fps. But I'm sure it's the same for everyone.

 

Anyway, he's not got an issue with fps.

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What does triple buffering even do?

 

And why would i be getting blurries when vsync and triple buffering is turned on

 

Bizzare

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Well, the triple buffer refers to the three screen memory storage areas the GPU uses for frames being made and displayed. There is a front buffer that is currently being fed to the screen, then there are two backbuffer frames. Any one of the backbuffer frames is being drawn by the sim, the other is ready to be switched with the front buffer. So with triple buffer there's never any waiting to switch the front buffer with a completed buffer frame, since there's always one of the two available, while the other can be drawn. So the CPU and GPU go full steam ahead. So can introduce blurries as it leaves too little time for the background tasks to populate the tiles.

 

With the VSync, that synchronises the GPU display with the output device feeding the screen, not to be confused with the vsync of a raster monitor. If the GPU hasn't finished a frame and the buffer run out, due perhaps to too much detail, then it waits on that frame. Without VSync, displays the same frame until the new one can be switched in.

 

So that's why I suggested to try those two methods running at 30, instead of 60 fps.

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With my new system I use Triple Buffering with V-Sync off and I am getting incredible frame rates. I guess it works differently for each person. 

do you have triple buffering turned on in nvidea inspector / control panel?

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Well, the triple buffer refers to the three screen memory storage areas the GPU uses for frames being made and displayed. There is a front buffer that is currently being fed to the screen, then there are two backbuffer frames. Any one of the backbuffer frames is being drawn by the sim, the other is ready to be switched with the front buffer. So with triple buffer there's never any waiting to switch the front buffer with a completed buffer frame, since there's always one of the two available, while the other can be drawn. So the CPU and GPU go full steam ahead. So can introduce blurries as it leaves too little time for the background tasks to populate the tiles.

 

With the VSync, that synchronises the GPU display with the output device feeding the screen, not to be confused with the vsync of a raster monitor. If the GPU hasn't finished a frame and the buffer run out, due perhaps to too much detail, then it waits on that frame. Without VSync, displays the same frame until the new one can be switched in.

 

So that's why I suggested to try those two methods running at 30, instead of 60 fps.

 

Interesting information.  So in order to test should we be flying in an area with heavy hit on frames and then what should we be looking for when following your two methods and comparing to unlimited in P3D and no limit in NI ?

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Testing should be done with little or no AA.

 

Setting the NI limit of 30fps and P3D Display Settings to Unlimited fps + VSync=On + Triple Buffer=On is far less demanding than setting the Fixed fps slider to 30.

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Try this Harry,

 

Set the 30fps limit in NI.

 

Display Settings set Unlimited, VSync On, and Triple Buf On.

Look at the shift-z fps you should see it around 30.

 

or

 

Set the 30fps limit in NI.

Display Settings set 30fps fixed on the slider, set VSync Off and Triple Buf Off.

 

Also I recommend setting HT On and affinity with four LPs one per core.

 

prior to applying this setting (30fps limit in ni and vsync on , unlim frames etc..) my core 0 was being taxed fully and the cpu usage overall was 55 to 60 ish and p3d was microstuttering et all.

 

Now the cpu usage is down to 35 to 40 and core zero is 50% utilized and p3d runs absolutely smooth !

 

thank you steve ! Also could you please explain how this could have happened ; the cpu usage reduction i mean ...

 

kind regards,

 

jaff

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Steve, why the option NVI at 30 and also 30 locked in P3D ?

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Steve, why the option NVI at 30 and also 30 locked in P3D ?

Hi Gerard,

 

I've demonstrated before that applying the limiter and the fixed rate combine to produce a smoother result. Same as with FSX 1/2 refresh.

 

The fixed rate creates a look ahead buffer that requires a very powerful machine. I know folks say "I'm seeing 45fps can I lock at 40?" You can but it won't work well. If you are seeing 60fps you can lock at 30.

 

But the limiter + Vsync + TB + unlimited is far less taxing. The locked frame rate bangs on creating the look ahead buffer irrespective of refresh or limit, and any stutter will deplete the buffer and it takes good performance to refill it.

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Hi Gerard,I've demonstrated before that applying the limiter and the fixed rate combine to produce a smoother result. Same as with FSX 1/2 refresh.The fixed rate creates a look ahead buffer that requires a very powerful machine. I know folks say "I'm seeing 45fps can I lock at 40?" You can but it won't work well. If you are seeing 60fps you can lock at 30.But the limiter + Vsync + TB is far less taxing. The locked frame rate bangs on creating the look ahead buffer irrespective of refresh or limit, and any stutter will deplete the buffer and it takes good performance to refill it.

Steve,

 

Tomorrow I am going to try this.

 

At this moment with P3D set to Unlimited I get fps of 27-37 at a very detailed airport with AI traffic and several cloud layers. Unlimited is FFTF = 0.01

With P3D set to 30 that drops to 17-26.

Therefore I am using the NVI limiter set to 25 and my monitors to 25 too.

 

I hope that with setting P3D to 25 too not will drag my fps to below 25 and I will loose the advantage.

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I tried this setting - Lock to 30 frames in P3D, turn on vsync and triple buffering and also lock frames to 30 in NI. (running 60HZ monitor)

 

Running A2A Comanche with GTN 750, clouds at KJAC I stayed between 29.5 and 29.7 flying thru mountains to the NW.

 

Just prior I was running lock to 30 in P3D, no vsync, no triple buffering and no NI. During same trip I would get 26 to 29 fps.

 

So Steve's recommendations for a "look-see" setting was a bit of a plus for me. One small hitch, I did get a slight pause (almost unnoticeable), but after about 6-8 minutes it seemed to settle down and run better. 

 

I also want to add that with the new settings, things seem "snappier" especially outside viewing. Also forgot to mention that along with GTN 750 I'm running ASN on networked machine.

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Ok, so after some testing in P3D v3.2, I have to agree that 30 locked in Nvidia Inspector and Unlimited frames w/ Vsync and Triple Buffering in the sim is the golden ticket for my system. Thanks for the suggestions Steve! 

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It's good, they've done a lot of work on that at LM guys. You're welcome, thanks for the feedback!

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Can fps limiting be done via the nvidia control panel at all? I'm assuming not nor can I find any obvious setting there but maybe I'm missing it? So I guess it's time to install NI again and give this a try then.

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No fps limit is not in the NCP. But anyway, NI won't mess things around used carefully. Always be sure to start from a fresh NI profile especially when we get a new driver... go into NCP and Restore/Apply the Prepar3D profile, this deletes the NI setup. So if we go to NI there will be no Prepar3D profile ready. So before closing NCP, we can make an adjustment in that profile page, like set power management to prefer Max Performance, and making that one change reintroduces a fresh profile in NI. Now close NCP and run up NI, we find a fresh profile in NI.

Setting as low as 30fps or 29fps is possible. Setting lower values of fps requires editing the CustomSettingNames_en-EN.xml found in the NI program folder.

 

..
..
<!-- added -->
        <CustomSettingValue>
          <UserfriendlyName>26 fps</UserfriendlyName>
          <HexValue>0xF000001A</HexValue>
        </CustomSettingValue>
        <CustomSettingValue>
          <UserfriendlyName>27 fps</UserfriendlyName>
          <HexValue>0xF000001B</HexValue>
        </CustomSettingValue>
        <CustomSettingValue>
          <UserfriendlyName>28 fps</UserfriendlyName>
          <HexValue>0xF000001C</HexValue>
        </CustomSettingValue>
<!-- original -->
        <CustomSettingValue>
          <UserfriendlyName>29 fps</UserfriendlyName>
          <HexValue>0xF000001D</HexValue>
        </CustomSettingValue>
        <CustomSettingValue>
          <UserfriendlyName>30 fps</UserfriendlyName>
          <HexValue>0xF000001E</HexValue>
        </CustomSettingValue>
..
..

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I tried 30NI + VSYNC + TB + UNLIMITED. It isn't the silver bullet for smoothness but it is better. I found I had to increase it to 35NI to make the terrain panning look as smooth as I get with 30FPS in FSX locked to 1/2 Vsync. Why that is I don't know. Any theories?

 

EDIT: By terrain panning I actually mean terrain rotation during a tight turn.

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I tried 30NI + VSYNC + TB + UNLIMITED. It isn't the silver bullet for smoothness but it is better. I found I had to increase it to 35NI to make the terrain panning look as smooth as I get with 30FPS in FSX locked to 1/2 Vsync. Why that is I don't know. Any theories?

 

EDIT: By terrain panning I actually mean terrain rotation during a tight turn.

By setting the 35 limit for P3D possibly means that it looks better because there's simply less time between frames, and possibly points to an unstable fps underlying the sim compared to FSX. But if you had FSX locked rather than just limited by the 1/2 vsync, it would do better on a 60Hz monitor in exclusive mode any day. What's the CPU and AM used?

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