Fast sync capping frames

Discussion in 'Videocards - NVIDIA GeForce' started by Goutan, May 6, 2017.

  1. Goutan

    Goutan Master Guru

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    I noticed an issue yesterday where enabling fast sync (I also have g sync on) caps my frame rate at my monitor's refresh rate. I made a lot of changes recently so I'm having a hard time tracking down the cause. Yesterday I installed a new graphics card and updated to driver 382.05. I also very recently installed the creators update with game mode enabled. So far I've tried disabling game mode but it doesn't make a difference.

    Does anybody know why the frame rate is being capped? When I set fast sync I do it through global settings so the games shouldn't be using vsync. I've tested and seen the issue on multiple games.

    As a side note, if I'm imagining that fast sync had an uncapped frame rate before, feel free to call me out on being dumb :)
     
  2. Goutan

    Goutan Master Guru

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    That's the set up that I resorted to. I used to have fast sync on for shooters like over watch when I would get 300 fps. I forgot where I read that it was the best setting to pair with gysnc..

    Are there any drawbacks to having vsync off at higher frame rates?
     
  3. Goutan

    Goutan Master Guru

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    I wish my eyes were fast enough to notice the input lag in most games. Maybe if I was 18 again. That said, I do notice the difference in FPS games. Vsync feels like someone is pulling my mouse away from me. I'll test it out though and see which way I prefer. I was really happy with fast sync while it lasted though. It had low input lag and no screen tearing.

    Also with how many games have a custom option to limit their frame rate now, vsync off shouldn't be the headache that it has been in the past.
     
  4. RealNC

    RealNC Ancient Guru

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    Nope. The best setting is g-sync on, vsync on in nvcp, vsync off in-game, and use a frame rate cap to set max FPS ~2-4FPS below max refresh rate. For 144Hz monitors, set the frame limiter in the Overwatch in-game settings to 140FPS.

    This way you will always have g-sync active, and the g-sync module will do frame time variance compensation to hide any tear lines (this is controlled by the nvcp vsync setting.)

    More details about this:

    http://forums.blurbusters.com/viewtopic.php?f=5&t=3073
     
  5. Goutan

    Goutan Master Guru

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    Well it looks like I'll be using frame limiters now. Thanks for the help guys!

    Also, RealNC, that link is gold - I've had a G-sync monitor for months now and based on those charts it looks like I haven't even taken advantage of it.
     
  6. tsunami231

    tsunami231 Ancient Guru

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    I read that and found to be rather confusing, maybe it just me
     
  7. RealNC

    RealNC Ancient Guru

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    That is quite common with owners of g-sync monitors. They think g-sync has lowered their input lag, while in reality it's just placebo. They're using v-sync because they didn't cap their frame rate :)

    It's safe to say that a large portion of g-sync owners don't actually use g-sync in all cases, they just think they do. They only end up using it when their FPS falls below max refresh.
     

  8. RealNC

    RealNC Ancient Guru

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    TL;DR: If you don't cap your framerate to about 2-4FPS below your max refresh rate, you're not using g-sync. If you don't enable vsync together with g-sync, then you can still get tearing at the bottom or top of the screen. Enabling vsync + gsync at the same time has no input lag penalty if you cap your frame rate.

    The rest of the post goes through quite scientific input lag tests that show why the above is true and why it's the "perfect" gsync setup. ("Perfect" is quotes because some people might still prefer vsync off for various reasons, like when playing games at 300FPS, like CS:GO and such.)
     

  9. RealNC

    RealNC Ancient Guru

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    If your frame rate reaches the max refresh rate, g-sync is disabled. So you're not using g-sync when that happens. You're using vsync instead (if you have v-sync enabled.) That means your input lag triples, or worse.

    Usually, that means going from ~15-20ms of input lag when you're below max refresh (g-sync is used) to ~40-60ms input lag when you reach max refresh (g-sync is disabled.) These values of course depend on the game, your frame rate and your max refresh rate. But in general, once you hit vsync mode, your input lag triples in most cases.

    To make sure you're always using g-sync, you need to make sure your frame rate does not reach the max refresh rate. To do that, you need to cap your frame rate. The minimum value for this seems to be 2FPS below max refresh. I use 4FPS, to make sure (140FPS on 144Hz.)

    This might not be a huge issue for 144Hz (and higher) monitors. Because even without g-sync, 144Hz vsync has quite low latency, so many people don't notice. But it's a big issue for 75Hz and especially 60Hz g-sync monitors. There, you're pretty much always hitting the max refresh, and as we all know, 60Hz vsync is quite... crap :p Floaty mouse, huge lag. What people then do, is disable vsync, which gets you tearing, or enable fast sync, which gets you micro-stutter. The end effect is that these people paid for g-sync, but end up not using it most of the time, because they don't know that you need to cap your frame rate to make sure you're using g-sync.
     
    Last edited: May 7, 2017

  10. RealNC

    RealNC Ancient Guru

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    Btw, Battle(non)sense has created some very solid videos on these issues, with actual measurements (so no placebo opinions, just facts). Here's one of them:

    https://www.youtube.com/watch?v=rs0PYCpBJjc

    He also discovered that using NVidia Inspector to limit FPS causes too much input lag (almost as bad as plain old vsync), and that if the game doesn't have a built-in limiter, it's best to use RTSS and not Inspector.
     
    Last edited: May 7, 2017
  11. RealNC

    RealNC Ancient Guru

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    Well, it does have no effect if your FPS maxes out. It only has an effect when your FPS drops.

    If you're playing a game that never drops below max refresh, then g-sync altogether will have no effect. For example, Overwatch and Doom 4 are games that on powerful PCs will never drop below max refresh on 144Hz monitors. G-sync will never have an effect there. You are going to get input lag, tearing or micro-stutter virtually 100% of the time.

    I think it's useful to inform people of this issue, and for that, it's necessary to use phrases like "g-sync has no effect", and then proceed to clarify what that means exactly. *When* does it have no effect, and *why* does it have no effect. :)
     
  12. RealNC

    RealNC Ancient Guru

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    OK, dude, if you have nothing to say other than trying to pick up a fight with people who are trying to help, then I'm afraid I'm going to have to ignore you.

    All the information as to "when and why" was already posted by me with links to the relevant information.
     
    Last edited: May 7, 2017
  13. Agent-A01

    Agent-A01 Ancient Guru

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    Are you on crack?

    You seem to have an issue with comprehension.
     
  14. Goutan

    Goutan Master Guru

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    I see that this thread has gone in a slightly different direction BUT I want to report that changing the settings according to the recommendations here has significantly lowered my input lag! As I stated earlier, it's hard for me to notice a few milliseconds of change so the fact that I can feel the difference is really exciting!

    I downloaded RTSS, capped my framerate at 142, made sure Gsync was enabled, and ended up turning off vsync/fastsync. After a 5 hour Overwatch session I can honestly say, I've never been as satisfied with my computer set up. I wish I new all of this from day one of getting my monitor.

    Thanks again!
     
  15. RealNC

    RealNC Ancient Guru

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    If you use the in-game limiter of Overwatch, this should reduce your input lag further. In fact, it should reduce it to the same levels as no sync at all.

    However, it seems that on some systems with the "creators update" of Windows 10, you might need to cap more than just 2FPS lower. We don't know yet what causes this. Some people (including BNS with his thorough test videos) fixed the issue by switching the Windows power management profile from "balanced" to "high performance."
     

  16. Agent-A01

    Agent-A01 Ancient Guru

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    He gave a comprehensive answer and gave a link answering the same question.

    Calling his legit answer 'smug' just labels you as an asshat.

    If you don't understand what he said then that is your issue as he answered your question.
     
  17. cryohellinc

    cryohellinc Ancient Guru

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    If you have G-sync, dont use Fastsync. Gsync works only below your monitor refresh rate (lets say its 144hz as an example) in combination with V-sync (not the adaptive one).

    To get best result in terms of latency do this:

    Cap fps in Nvidia control panel using Nvidia Inspector to 142fps - Choose Fps cap method 2 for Global profile.

    Set Global profile in Nvidia Control Panel to Vsync On.

    Set G-sync to Fullscreen mode.

    Set Game mode to On.

    This results in lowest latency times, with Gsync always on and no stutter.
     
  18. RealNC

    RealNC Ancient Guru

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    That is not correct. Do NOT use Inspector. It is going to give you input latency that is almost as bad as vsync.

    Always ONLY use the in-game limiter, and if the game does not have one, then use RTSS. Never use Inspector for this if you care about input latency.
     
  19. mbm

    mbm Member Guru

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    Gsync ON all other sync OFF.
    CAP frames to 140.
    Thats it.
     
  20. CenoRazer

    CenoRazer New Member

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    Need help

    I need help guys...

    bout this gsync issue...

    So...what I want is>> game (FPS battlefield 1 overwatch and such) to run at 144 fps....i have a gsync monitor at 75hz...laptop...the game can run at 144fps at lower graphics and competitively that is what i want...so what is the best setup?

    1) GSYNC ON / VSYNC ON / ingame- vsync off >> frame limiter to monitor refresh rate; = i will have 75 fps right? and what about input lag? it's competitive enought?

    2) GSYNC ON / VSYNC OFF / ingame vsync off >> frame limiter to 144fps; = i will have 144 fps but what about input lag? it's competitive?

    3) GSYNC ON / FAST SYNC ON / ingame vsync off >> frame limiter tp 144fps; = i will have 144 fps but what about input lag? it's competitive?

    4) usually, i have a asus vg248qe monitor 144hz that i can pair with my laptop...i put GSYNC OFF / VSYNC to 3dapplication default / ingame vsync off >> i have more that 144fps...it's competitive? what about input lag?

    Thanks in advance
     

  21. Agent-A01

    Agent-A01 Ancient Guru

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    1. This will be Vsync ON = bad input lag.

    2. This will be Gsync off = no input lag

    3. Fast sync has little input lag but you will experience stutter and irregular frame pacing. FPS minimum of 2x refresh rate, preferably 3x with stable frame rate to not experience weird frame pacing. Unlikely you can achieve this so skip fast sync.

    4. No input lag.
     
  22. CenoRazer

    CenoRazer New Member

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    Thank you so much.

    I will go with the second option when i am without my external monitor.
     

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