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Requesting Scanline Sync Tutorial

Discussion in 'Rivatuner Statistics Server (RTSS) Forum' started by EerieEgg, Nov 2, 2018.

  1. AsiJu

    AsiJu Ancient Guru

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    Yeah, SyncScanLine0=200 means the tear line should be visible at the bottom (200th horizontal line from the bottom up) if I understand correctly. As negative values go below the bottom of the screen (=hide tearline).

    GPU usage affects scanline position accuracy though. With high or very varying usage the scanline might be "oscillating" a lot and if you try to look at just one spot perhaps you miss it.
    Framerates below your refresh rate will naturally cause a visible tear line as Vsync is off and framerate doesn't match refresh rate anymore.

    PS: entire point of S-sync is to have Vsync smoothness without actually using Vsync while hiding the tear line. So if you can't see it, be happy :)

    Also there are no universal settings that should work. GPU headroom, monitor type and resolution, game you're playing all matter.
    Chances are you need to use different scanline target value for all your games for best results.
     
    Last edited: Mar 6, 2019
  2. Andy_K

    Andy_K Master Guru

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    Nope
    Positive values are from top to bottom, negative are from bottom to top.
    1080p Displays have more than 1080 scanlines but they display only 1080. The surplus scanlines are there to give time for synching. A 1080p display typically has 1125 scanlines in total but this may vary.
    If you want to set RTSS for 50 scanlines before synch wraps around you may calculate by yourself 1125 - 50 and set SyncScanLine=1075 or you may let RTSS do the calculation even whilst not knowing how many scanlines your display has in total by setting SyncScanLine=-50
     
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  3. AsiJu

    AsiJu Ancient Guru

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    Ah ok, other way around then.

    In that case @Litzner tearline should be at the top of the screen with SyncScanLine=200
     
  4. belmonkey

    belmonkey Member

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    Does the low lag V-sync on method work still? And if so, does it work any better with Enhanced / Fast sync? I usually set my global fps cap to 60 and use E-sync, but apparently my monitor's refresh rate is 59.940. Does that mean I'm worse off with a solid 60 fps cap?
     

  5. Litzner

    Litzner Member

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    I thought negative values were supposed to drop the scanline off the bottom of the monitor, so -20 would be 1100? Because to calibrate the line off screen for no vsync+ssync you would set it for around -20 to -40 right?

    Or are we saying that a -20 would be roughly 1105, depending on the monitor? So they come from the bottom of the scanlines, not the bottom of the monitor?
     
    Last edited: Mar 11, 2019
  6. Unwinder

    Unwinder Moderator Staff Member

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    You thought it wrong.
     
  7. Litzner

    Litzner Member

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    I think the best form a low lag vsync right now is Ssync+Esync\Vsync. Setting the scanline to be 10-20% off the bottom of the monitor, so a SyncScanline0=880 (on 1080p) as long as you have the GPU overhead. You would have to turn off the global framerate cap.

    I have tried to do the framerate limiter and it doesn't seem to work as well for me, and it seems to have much more CPU overhead, but my CPU is getting a bit older now, so that could be just my setup.
     
    Last edited: Mar 11, 2019
  8. Litzner

    Litzner Member

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    And he had spoken! I couldn't have been wrong though... I must have been mistaken... ;)

    Thanks boss! I have some cfg's to adjust when I get home...
     
  9. belmonkey

    belmonkey Member

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    I was going for an option without having to have a lot of spare gpu usage for it to work (I want to push resolution / graphics as high as possible for a 60 fps cap). Overall though, would a fractional fps cap (at 59.94-.01) be a better option than a flat 60 fps cap?
     
  10. RealNC

    RealNC Ancient Guru

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    Of course. Why would it stop working? :p

    It works best if your cap it near your Hz, just slightly under. So if your Hz is 59.940, just enter "59.93" in RTSS. That's true for both normal vsync as well enhanced/fast vsync.

    Note: you can use scanline sync instead of a normal FPS limit with enhanced/fast sync (that's because the game runs with vsync off, so scanline sync will work.) When doing that, the point is not to reduce tearing (because enhanced sync will do that), but to stabilize latency. Of course you still get issues when the GPU doesn't have enough headroom left.
     

  11. belmonkey

    belmonkey Member

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    So short of scanline sync, can I go for max GPu usage with this method and still get good results? Is E-sync better for latency than in-game V-sync? And for a 30 fps cap, would 29.96 work alright with normal V-sync?
     
  12. RealNC

    RealNC Ancient Guru

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    As long as you reach the FPS target, it will work fine, regardless of GPU usage.

    With an FPS cap, it's probably the same (going by fast sync on nvidia; e-sync works in the same way.) But I don't think anybody measured. In the past (prior to getting a VRR display) I preferred vsync though, not fast sync, since vsync has less stutter issues. I never noticed a latency difference between vsync and fast sync when using the -0.01 FPS cap.

    But if you're not seeing any weird micro-stutters or hiccups with e-sync, then you might as well use it.

    There will be some stutter, because when FPS capping much lower than Hz, then a single skipped frame due to lack of sync will translate to a 33ms freeze (that how long a 30FPS stays stays on the screen.) It might be worth trying vsync OFF with x/2 scanline sync in that case, which will sync perfectly at half Hz. Scanline sync x/2 usually works well because the GPU has more headroom left due to half FPS.

    If the GPU load is still too high even at x/2 scanline sync and you would want to use normal vsync, you would use 1/2 vsync on Nvidia (through inspector) and use an RTSS cap of Hz / 2 - 0.01. This would give smooth 30FPS (perfectly flat frame times) without stutters. But I don't know how to do that on AMD.
     
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  13. TheDeeGee

    TheDeeGee Ancient Guru

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    So for WoW anything between -10 and -70 works.

    Should i pick something in between then?
     
    Last edited: Mar 12, 2019
  14. Malik Sajid

    Malik Sajid Member

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    You do it on AMD through RadeonPro, you just need to set the vsync controller in the tweaks tab to 'Always On (Double Vsync)'.
     
  15. Norhtman_Ast

    Norhtman_Ast New Member

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    Hi,

    I ve been using SSync for a while but I dont know why suddenly it wont work anymore, until yesterday, and then today it doesnt work again. I think the hook is the issue but Im lost. Any ideas?
     

  16. 5TGLk

    5TGLk New Member

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    I've been experiencing an issue with scanline sync. When games are first launched, the tearline is where I want it to be. Off screen and out of sight. Over time however, the tearline will drift. It keeps slowly moving until it comes back into view and often settles near the middle of the screen. What could be causing this?

    Edit: I fixed this problem by ensuring that my gaming monitor was the first monitor seen by windows. It was previously syncing to my other monitor, which would obviously cause problems.
     
    Last edited: Apr 23, 2019
  17. AlexanderV

    AlexanderV New Member

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    Greetings everyone.

    So I have been trying to figure out how scanline sync works and hopefully benefit from this great feature.
    I own an ASUS ROG STRIX SCAR II gaming laptop paired with a GTX 1060 6GB and an i7 8750H. I am not the most demanding gamer in the world, I am extremely satisfied with 1080p@30fps at High settings but I hate tearing/stuttering with a passion. I usually go for a 30fps lock through RTSS and turn on Vsync to avoid tearing. I choose to accept the input lag and the micro stuttering this offers.
    Due to my laptop using the Nvidia Optimus technology, Half V-Sync/Fast Sync is not an option.
    I have been playing arround with the feature, setting Scanline Sync to x/2 and changing values from -1 all the way up to -300 with no difference at all. Vsync is turned off both in game and through the nvidia control panel and I am running the game at fullscreen. My question is, could this feature not be available due to Nvdia Optimus? Everything has to first go through the intel display adapter, correct? Or am I doing something wrong? GPU utilisation is bellow 60 percent. I am trying this in games like the Witcher 3, AC Unity, Metro Exodus, Shadow of the Tomb Raider etc. Tearing is visible even at the menus where GPU utilisation is extremely low!

    Thanks in advance.
     
  18. jetraw

    jetraw New Member

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    Hi guys, can you help me?
    If my monitor has 1480p (1440+40), what value will be correct, -20 or -40 for Scanline sync?
     
  19. Andy_K

    Andy_K Master Guru

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    Depends on your graphics card and how demanding the game is...

    There is no short answer.
    Read the thread.
     
  20. Siberto2

    Siberto2 Member

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    Hi guys, I've read some guides but there is a lot of confusion.
    1) Should I use negative numbers? E.g. with a 60Hz monitor scanline sync -60.
    2) Does it only work on full screen?
    3) C:\Program Files (x86)\RivaTuner Statistics Server\Profiles I've read I need to edit files adding SyncHotkeys=1 under [Framerate] but when I try to save it tells me I have no permissions.
    4) Should I set V-sync off on NVIDIA panel or I can keep the "use the 3d application setting" and off in game?
     

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