Input Lag: Traditional V-Sync VS Windowed Mode?

Discussion in 'General Software and Applications' started by EerieEgg, Nov 26, 2018.

  1. EerieEgg

    EerieEgg Master Guru

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    Hi there guys,

    One thing I've been wondering about lately since I don't yet have G-Sync is input lag/latency when using:

    1) Fullscreen with V-Sync (Double Buffered)

    OR

    2) Borderless Windowed Mode

    Since my understanding is Windowed Mode is triple buffered I would assume it adds more input lag than #1, however, in practice this has not been the case going off of "feel" in game.

    For example, I tried a few titles in borderless windowed mode with the framerate capped at 60 fps using Rivatuner then I tried the games in fullscreen mode with double buffered vsync capped at 60 fps using Rivatuner and it "felt" to me as though the borderless windowed mode had a lot less input lag.

    Are any of you aware which has more input lag between the two?

    I had heard using borderless windowed would net you fewer fps overall, but assuming both fullscreen/windowed are capped and hitting the same fps, is borderless windowed mode a lower input lag way to achieve no-tearing?

    Thanks for your time, I really appreciate it -- have been having trouble tracking this info down online.

    EDIT (P.S.)

    #3) Does capping your framerate have any impact on input lag while using Borderless Windowed Mode to remove/reduce screen tearing? My understanding based on other threads here is if you're using traditional V-Sync you want to be capping 0.01-0.1 beneath refresh rate for best input lag results, but I noticed in Borderless Windowed Mode, the fps could remain completely uncapped while (most) tears were removed -- though occasional a single tear would creep in (not sure why this would happen atm).
     
    Last edited: Nov 26, 2018
  2. EerieEgg

    EerieEgg Master Guru

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    @RealNC Sorry for the trouble, just figured I'd tag you since you've been very knowledgeable regarding this sort of thing in the past. Thanks for your time
     
  3. RealNC

    RealNC Ancient Guru

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    Windowed mode with vsync OFF will have less input lag than fullscreen with vsync ON. That's normal. It's basically the same as fast sync, except fast sync is even lower input lag than windowed mode.

    Windowed mode with vsync ON however will have more latency than fullscreen with vsync ON, unless the game is using the new borderless mode (called "independent flip mode"), or Windows 10 is redirecting the game from normal borderless mode to independent flip mode. In that case, latency is the same as exclusive fullscreen.

    Capping your FPS when using windowed mode vsync OFF has the same effect as capping your FPS when using fast sync.

    Overall, the whole thing gets a bit confusing, because there's three different modes: exclussive fullscreen, windowed mode (this includes borderless and bordered windows), and independent flip windowed mode (this only works with borderless windows.) It's not easy to tell in which mode a game runs in. You need to do some tests to figure it out.

    All of these tests must be performed with vsync forced OFF.

    If you don't see any tearing, then the game is using normal windowed mode. Other effects of that mode include the ability to alt+tab out of the game and back instantly, and changing the Windows audio volume will show the volume bar in the upper left corner of the screen.

    If you see tearing, but you can still see the Windows audio volume bar when you raise/lower the volume using your keyboard, and tearing stops for the duration the volume bar is visible but it starts tearing again once the volume bar disappears, then you're using independent flip windowed mode. This is the best mode, since it has the same latency as exclusive fullscreen but allows fast alt+tab and also allows you to see the Windows volume bar.

    If you see tearing, alt+tab takes a long time and you can't see the Windows audio volume bar, then you are most probably in exclusive fullscreen mode.

    Once you know in which of these mode the game is running, then you can argue about the effects of vsync and frame capping.
     
    Last edited: Nov 26, 2018
    akbaar and EerieEgg like this.
  4. EerieEgg

    EerieEgg Master Guru

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    Thank you very much! This was very helpful for me
     

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