Why does traditional V-Sync look smoother than G-Sync at the same framerate?

Discussion in 'Videocards - NVIDIA GeForce' started by BlindBison, Jul 31, 2021.

  1. BlindBison

    BlindBison Master Guru

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    For example, I have a 1080p fixed refresh 60 hz panel and a 1440p 144 Hz G-Sync panel and this is something I've observed repeatedly at 30 or 60 FPS capped.

    So, setup 1 is the fixed refresh panel using Nvidia driver level Half-Refresh Rate V-Sync (30 fps) in conjunction with a framerate limit (RTSS or driver level limiter for example).

    Setup 2 is the G-Sync panel with G-Sync ON + V-Sync ON (for the frametime compensation module) + an FPS limit at 30 or 60 (RTSS or driver level limiter).

    My observation's been regardless of game, the traditional V-Sync looks noticeably smoother for ... some reason while G-Sync looks choppy/has more discernible frame gaps, but input latency is better.

    Why exactly is this the case? I would think 30 fps provided the limiter was doing a good job with frametimes should look exactly the same, but it doesn't. Does it have something to do with how G-Sync handles lower framerates? It's less apparent at 60 given the additional frames, but you can still tell there too. Thanks,
     
  2. RealNC

    RealNC Ancient Guru

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    You need to also compare both panels too at the same setting. That is, use 60Hz, g-sync OFF and vsync ON on the 144Hz panel. Does that result in the same difference?

    Also make sure you compare both panels not only using the same settings, but also the same hardware setup. If you have two different PCs that you use those displays with, then make sure you test both using the same PC.

    For what it's worth, I see exactly zero difference when I run my panel at 144Hz g-sync with a 30FPS cap, and when I run it at 60Hz without g-sync and a 30FPS cap with 1/2 vsync. Both look identical.
     
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  3. demented brave

    demented brave Master Guru

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    My old monitor was a 1080p 60hz and using vsync running at 60fps it always looked smooth. Now I have been using a 1440p 144hz g-sync monitor for several years and anything under like 70fps looks choppy to me. Don't know if it is just that I got used to the higher refresh rate or if there is something else going on, but I won't go back to 60hz now.
     
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  4. RealNC

    RealNC Ancient Guru

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    If it's a larger display, that's normal. The larger the display is, the higher FPS/Hz you need to keep things looking smooth. The simple explanation for that is that the larger the display size gets, the larger the distance of moving objects between each frame is. This of course looks choppier and blurrier.

    You can observe this effect by playing at 720p @ 60FPS unscaled, so that you get a small window in the center with black bars around it. 60FPS will look smoother compared to fullscreen.
     
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  5. BlindBison

    BlindBison Master Guru

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    Thanks that's helpful, I'll redo the testing with the G-Sync monitor V-Sync OFF tomorrow. Don't get me wrong 30 FPS on the G-Sync panel does look "smooth" in the sense that there's no hitching like you'd get with double buffered V-Sync when the framerate "misses", but when both reach 30 FPS there is a difference in visual smoothness to my eye.

    But I've not yet tried the G-Sync panel with G-Sync OFF set to 60 Hz, good idea. Thanks!
     
  6. cucaulay malkin

    cucaulay malkin Ancient Guru

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    one - cause it's 30hz
    two - cause vsync at 30fps intoduces so much lag it may appear less choppy
     
  7. RealNC

    RealNC Ancient Guru

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    Also note what I wrote above. The smaller panel will appear smoother simply because of its size. You can try and equalize both using a smaller resolution without scaling.
     
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  8. aufkrawall2

    aufkrawall2 Master Guru

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    Sounds silly at first, but I think the inertia really makes it subjectively appear smoother. I haven't noticed any differences on the same screen with fixed 60Hz vsync vs. 60fps VRR when having constant smooth motion (e.g. panning camera by keeping a keyboard button pressed). Anyway, the 60Hz look terrible when the eye/perception was used to more right before, as perception is heavily vulnerable to comparisons (which is why also manual color temperature adjustments are destined to be bad).
     
  9. RealNC

    RealNC Ancient Guru

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    It's not silly. When playing a game that has some in-game benchmark, like most Codemasters racing games, 60FPS looks smoother than when you actually play yourself. Same when you record your 60FPS gameplay to a 60FPS video. When you watch the video, it feels smoother, as if it's magically a higher frame rate, but it's not.

    Not sure what causes this effect, but it's there.
     
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  10. southamptonfc

    southamptonfc Ancient Guru

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    I didn't think GSync works at 30fps?

    Anyway, you're putting loads of other crap in the chain (half-refersh rate and/or framerate limiter), that will screw with how gysnc is supposed to work.

    Why do this test on 2 different panels? Use 1 panel and cut out all the other stuff.
     

  11. Pyrage

    Pyrage Master Guru

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    High refresh rate panels look like crap when you use them with lower rates. A 144hz monitor @60hz won't look as smooth as a native 60hz monitor.

    It's fine if you're gaming or whatever and thanks to free/gsync, the refresh rate is constantly changing. If you cap it to a constant 60 there's where you start to see differences.
     
  12. tsunami231

    tsunami231 Ancient Guru

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    does 144hz monitor look better then 60HZ monitor even if it not pushing the same fps as the hz? 144hz @60fps look smoother then 60hz @ 60fps? been while since i had access to one so i cant test
     
  13. Pyrage

    Pyrage Master Guru

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    60hz@60fps monitor looks way better than 144hz@60. For some reason, a 144hz@60 feels like its @ 30 or 45, most 144hz don't like to stay <100hz.
     
  14. RealNC

    RealNC Ancient Guru

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    It works right down to 1FPS even.
     
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  15. Cave Waverider

    Cave Waverider Maha Guru

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    Without VRR it also depends wether the refresh rate is multiple of the framerate or not. For example, 60 FPS at 120Hz will look and feel better than 60FPS at 144Hz. Still, 60 at 60 will probably be better.
     
    Last edited: Aug 1, 2021

  16. tsunami231

    tsunami231 Ancient Guru

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    eh so i just gona game on 60fps reguardless i should look for panel that 60hz or mutiple of it.... one more reason i will probably stay with 60hz panel
     
  17. RealNC

    RealNC Ancient Guru

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    You should look for a high refresh rate panel with g-sync. I play some 60FPS games @ 144Hz g-sync and input lag is much better compared to 60Hz without g-sync. Snappy and responsive.
     
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  18. tsunami231

    tsunami231 Ancient Guru

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    Unlikely less i can find 4k 28" panel in price range which 300 or less, I do most my gaming PC and or Consoles on my 55" UHDTV so i dont see point in paying out the ass for Monitor tech that wont be used My monitor mostly use for web browsing and check email it been over 4 years since I really game on my monitor, cause I just output to my TV now
     
  19. Cave Waverider

    Cave Waverider Maha Guru

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    A nice 120Hz HDMI 2.1 TV with VRR may do the trick for you then. ;)
     
  20. BlindBison

    BlindBison Master Guru

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    Just an update, I tried the 144 Hz G-Sync screen set to 60 Hz Fixed Refresh output via the control panel.

    When I use Nvidia Inspector Half-Refresh V-Sync (or control panel half refresh adaptive v-sync) in conjunction with an RTSS framerate limiter it looks very smooth/I can hardly discern the frame gaps with a controller.

    When I switch it back to 144 Hz G-Sync mode then enable V-Sync + G-Sync and set the same FPS limit (30) the G-Sync one has a lot less input latency (noticeably less), but it does appear somewhat less "smooth" to my eye with more pronounced gaps between frames. It doesn't microstutter mind you, traditional v-sync when there are drops seems far worse in terms of handling drops, but in terms of just perceived visual smoothness while reaching the target I mean.

    In any case it's not really a big deal, just something I noticed since some games don't play nice/have asset streaming stutters on my rig unless I cap them quite literally to 30 FPS at which point they totally dissapear. For me Outer Worlds is one such title, but I tested the 30 FPS thing in a couple.

    Regardless, G-Sync overall is still better imo -- lower input delay and handles drops in fps below target more elegantly VS traditional V-Sync.
     
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