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Question VSync lowers performance even when it is disabled. Unity 2021.3.10f1 (DX11)

Discussion in 'Editor & General Support' started by unity_AkGames, Oct 3, 2022.

  1. unity_AkGames

    unity_AkGames

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    I disabled VSync in every quality setting and set Application.targetFrameRate to -1 and yet VSync takes more than half of the frame time. I did run an empty scene and i had the same problem.



     
    unity_AkGames, Oct 3, 2022
    #1

  2. enhawk

    enhawk

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    Screen Shot 2022-09-30 at 19.28.07.png this is turned off by default, does turning it on affect performance?
     
    enhawk, Oct 3, 2022
    #2

  3. unity_AkGames

    unity_AkGames

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    Yes. When i enabled that option, the frame rate was fixed to 60 Fps. But the screenshot above is from profiling a build of the game and not from the play mode.
     
    unity_AkGames, Oct 3, 2022
    #3
    enhawk likes this.

  4. CodeSmile

    CodeSmile

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    Do you happen to test this on an adaptive sync monitor? In that case, turning off vsync has no effect beyond the refresh rate of the monitor.
     
    CodeSmile, Oct 3, 2022
    #4

  5. Tautvydas-Zilys

    Tautvydas-Zilys

    Unity Technologies

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    That's not VSync. It's just waiting for your GPU to finish rendering. Look at your GPU usage in the task manager.
     
    Tautvydas-Zilys, Oct 3, 2022
    #5

  6. unity_AkGames

    unity_AkGames

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    GPU usage is at 9x%. But if the main thread is waiting for the GPU to finish rendering the frame why would the render thread says "WaitForGfxCommandsFromMainThread"?
    And i dont have this problem in other projects.
     
    unity_AkGames, Oct 4, 2022
    #6

  7. Tautvydas-Zilys

    Tautvydas-Zilys

    Unity Technologies

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    Render thread is idle, it has already submitted all the commands to the GPU and is waiting for more. The GPU is processing the commands and the main thread is waiting on that. Your game seems to be GPU bound (as in the performance is limited by the GPU performance).

    Since the GPU is pretty much maxed out, it can't run any faster.
     
    Tautvydas-Zilys, Oct 5, 2022
    #7
    unity_AkGames likes this.

  8. enhawk

    enhawk

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    I'm also getting this problem with builds in 2020 / 2021 on mac. Building with 2019 doesn't spin up the graphics card to max (some kind of vsync issue) - theres certainly something up here.
     
    enhawk, Oct 5, 2022
    #8

  9. Tautvydas-Zilys

    Tautvydas-Zilys

    Unity Technologies

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    Perhaps the scene is just more GPU intensive on Unity 2020/2021? At that point, it comes down to looking at assets, materials and all other things in the scene.
     
    Tautvydas-Zilys, Oct 5, 2022
    #9
    DevDunk likes this.

  10. unity_AkGames

    unity_AkGames

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    Dec 23, 2020
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    I see it now. Thanks!
     
    unity_AkGames, Oct 10, 2022
    #10