Should I Turn On V-Sync With Freesync..?

Discussion in 'Computer Monitor Forum' started by zeebaluch, Oct 23, 2017.

  1. Chastity

    Chastity Ancient Guru

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    Have you tried using CRU to extend the lower range of your FreeSync?
     
  2. Agent-A01

    Agent-A01 Ancient Guru

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    That is the global recommendation for gsync and freesync

    Vsync ON + FPS cap -3 of refresh rate

    The reason of you seeing input lag is normal. when FPS hits the ceiling of Freesync/gsync, Vsync will activate to ensure no tearing.

    That means Freesync is disabled while standard vsync is on.
    So what you are experiencing is quite normal.

    Since your monitor is 75hz, use a FPS cap of 72/3.
    74 is too close to the ceiling.

    Since frame limiters aren't perfect, you want at least 2-3 below refresh rate to ensure the FPS never touches the cap, otherwise you get input lag.

    There are so many people who do not understand Gsync/freesync that you get conflicting information everywhere which sucks for people like you trying to understand it all.
     
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  3. sheep

    sheep New Member

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    The Nvidia suggestion of turning on Vsync in the driver combined with Gsync and a frame cap goes out the window when it comes to Freesync because driver level Vsync doesn't work with AMD. Would you instead use the in-game vsync with an fps cap? AMD employees posting on reddit and their own forums suggest using Vsync and NOT limiting fps.... They don't seem to understand that you endure the full Vsync input lag penalty when you don't cap fps.

    It would be nice to see a similarly impressive article with extensive tests done to discover the most optimal Freesync settings but I guess I understand why customers of the much smaller company are left in the dark.
     
  4. Chastity

    Chastity Ancient Guru

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    Agent-01 and I debated on this for awhile, and the conclusion was that the info by AMD_Robert is outdated.

    Just disable VSync in-game and in driver, or set driver to Enhanced Sync, and set your FPS caps to maxframerate-3. If the game supports it, great. If not, use RTSS. If using Chill, set Chill to use your FreeSync range.

    I've had success with setting Sync to Enhanced Sync, VSync off in-game, and it was quite smooth. However, I don't bother as I now use Chill to keep power draw and temps down, so I am not going over my refreshrate anymore.
     

  5. yasamoka

    yasamoka Ancient Guru

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    No. V-Sync has to be on for frametime compensation to be on. I have tried both G-Sync and FreeSync and this behavior is identical. You need to keep V-Sync enabled even if you cap the framerate slightly below the refresh rate as there are frames that can miss the timing window and present faster than the refresh, causing a tearline often closer to the bottom of the display. Frametime compensation works by making sure the frame is delayed to align exactly with the scanout. This doesn't increase input latency - it merely scans out frames as fast as the scanout will allow, no more, no less. The only way to get lower latency is to let frames tear with a framerate above the refresh rate.

    Avoid Enhanced Sync completely when you have a FreeSync monitor. It will deliver a stuttery experience with FPS > refresh rate with roughly the same input latency at very high framerates and higher input latency at lower framerates (that are still above the refresh rate). Enhanced Sync delivers latencies better than V-Sync on, and very high framerates are required for latencies that match (or are ahead of) V-Sync off at FPS ~ refresh rate. So, mostly, no point to Fast Sync / Enhanced Sync when you have a high refresh-rate G-Sync / FreeSync monitor.

    So, V-Sync on in driver / game (only if the game does not introduce its own frame pacing), in-game (only if the limiter does not cause stutter) / RTSS FPS cap at ~ -3 below refresh rate.
     
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  6. Chastity

    Chastity Ancient Guru

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    My experience with VSync off, and now Enhanced Sync on as of 17.12.x, and FreeSync does not agree with your assertions. I have perfectly fluid playback as long as I am in the FreeSync range in all my games.
     
  7. yasamoka

    yasamoka Ancient Guru

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    Do you realize what Enhanced Sync is for?
    https://gaming.radeon.com/en/radeonsoftware/adrenalin/enhanced-sync/

    The only effect Enhanced Sync can have at framerates lower than refresh rate is that it enables triple buffering, which is negated by having FreeSync enabled (as that is a double buffer).

    At framerates above your refresh rate, you get jitter due to mismatched framerate and refresh rate as well as higher latency than V-Sync on, FPS cap @ 3FPS below refresh rate.

    It's horribly simple. Whenever your framerate is not very high, G-Sync / FreeSync should never be combined with Fast Sync / Enhanced Sync. There is no point in doing so. All you get is stutter and higher input latency when you go above your refresh rate, and the same, exact experience when your framerate is within the G-Sync / FreeSync range. Go ahead and disable Enhanced Sync, your experience with the framerate fluctuating within the range is exactly the same.
     
  8. sheep

    sheep New Member

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  9. sverek

    sverek Ancient Guru

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    without fps limiters? Nothing said about it. VSync does cap your framerate to monitor refresh rate.

    So with FreeSync, monitor drops refreshrate to match GPU fps and instead of stuttering (that caused by VSync alone), GPU just sends next ready frame without waiting on panel.
    So in this scenario, FreeSync is used to eliminate VSync stutter.

    I am not 100% sure on this though.
     
  10. Australis

    Australis Master Guru

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    Enhanced Sync is overrated
    https://forums.guru3d.com/threads/enhanced-sync-is-overrated.418552/

    How sweet! The divided opinions about FreeSync optimal settings outlive my thread.

    Having done some reading, I'm annoyed because...

    1. Some people keep mentioning AMD driver-level V-Sync. From the days of Catalyst, that driver-level V-Sync option only affects OpenGL titles!

    2. Some people assert FreeSync must work the same way as G-Sync. It is a theory to be examined.

    3. Some people swear by a frame-rate limiter solution and mention input latency all day. Curiously, it has occurred to me that RTSS frame-rate limiter breaks frame-pacing rendering gameplay horrible.

    For the love of God, just stick with FreeSync + V-Sync for the out-of-the-box gameplay smoothness. Don't mind the additional input latency unless you can really perceive it.

    # Don't fix what's not broken
     
    Last edited: Mar 27, 2018

  11. yasamoka

    yasamoka Ancient Guru

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    Didn't you get tired of bringing up the subject and regressing it every single time?

    Again, for the bajillionth time: FreeSync + V-Sync + FPS cap @ 3 below refresh rate.

    Since Nvidia driver-level V-Sync works across all APIs, the priority for V-Sync on Nvidia is 1) driver-level 2) game.

    Since AMD driver-level V-Sync works for OpenGL, the priority for V-Sync on AMD is 1) game 2) third-party 3) driver-level (if game is OpenGL).

    Works for both G-Sync and FreeSync. Tested by many, including myself. It works, fix your configuration / mention the game(s) where this abnormal frame-pacing behavior works. The general rule still holds. Please let this die already.
     
  12. mtrai

    mtrai Maha Guru

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    Seriously can we just let this go...anyhow here is the information on the various combinations directly from AMDRobert..This should explain it all.

    https://www.reddit.com/r/Amd/comments/4ypw5k/freesync_is_so_fcking_awesome/

    https://www.reddit.com/r/Amd/comments/4ypw5k/freesync_is_so_fcking_awesome/d8y6o8g/
    AMD_Robert
    Technical Marketing 19 points 1 year ago*

    FREESYNC WITH VSYNC

    If vsync is enabled, it is only active when the FPS is above or below your monitor's refresh rate range.

    If FPS is below, the monitor has no choice but to use vsync in the double or triple-buffer mode you've set. This will avoid tearing, but add input latency.

    If the FPS is above, the GPU will reject frames ("FPS cap") to keep the application inside the FreeSync window. It will enforce smoothness. You won't get the lowest possible input latency due to rejected frames, but no extra latency is being added.

    When your game is in the FreeSync window, this is the lowest possible input latency.

    FREESYNC WITHOUT VSYNC

    If you really care about input latency, then you can turn vsync off.

    If the app is inside the FreeSync window, FreeSync is active. This is the lowest possible input latency.

    If the app is below the FreeSync range, monitor will run at max refresh until the app's FPS gets back inside the DRR window. You will experience tearing, but no frames will be buffered or held as with vsync.

    If the app is above the FreeSync range, monitor will run at max refresh and your FPS can go however high it will. This sustains the lowest possible input latency because no frames are being buffered, held or rejected as with vsync. You will experience some tearing until the FPS falls back inside the FreeSync window and FreeSync resumes.

    IF YOUR MONITOR IS COMPATIBLE WITH FREESYNC LFC

    If your monitor has a sufficiently wide range to support our Low Framerate Compensation feature, this supersedes your vsync setting. It has lower input latency, no tearing, and no vsync stutter. It's much better than vsync.

    Most people want to leave FreeSync + Vsync enabled.

    PROS: GPU won't waste power/heat/noise on unused frames, game forced inside the FreeSync range as often as possible, no stuttering, no tearing.
    CONS: Lowest possible input latency will not be achieved if app goes outside of FreeSync range. Vsync stutter possible when app is below FreeSync window

    If you're a stickler for mouse latency, use FreeSync + vsync OFF.

    PROS: No stuttering/tearing inside FreeSync window, lowest possible latency at all times.
    CONS: Tearing possible when app leaves FreeSync window
    IF app FPS < min_refresh THEN Low Framerate Compensation (LFC) supersedes vsync

    https://www.reddit.com/r/Amd/comments/4ypw5k/freesync_is_so_fcking_awesome/d6zl13v/

    AMD_Robert
    Technical Marketing 30 points 1 year ago

    Do not use any sort of frame capping with FreeSync. The frame time analysis algorithms that govern FreeSync, FRTC or other methods will conflict and break both solutions. It's unnecessary. Here's why:

    The only time you'd want to turn off vsync with FreeSync is if the app's FPS can go way above your monitor's max refresh and you want the lowest possible input latency at the expense of a little tearing at high framerates. FRTC is the antithesis of this, so it doesn't make sense to use FRTC in this case.

    If you're not trying to get the lowest possible input latency, or the app's FPS stays inside your monitor's DRR window on the regular, then leaving vsync enabled will cap your framerate anyways. FRTC is redundant.

    FRTC is for people with regular ol' monitors who are playing low-demand games running in the hundreds of FPS, which just burns power and runs the fan faster than necessary.

    /Edit One thing to note if you have freesync use enhanced sync for the best combination as enhanced sync only engages outside the freesync range https://gaming.radeon.com/en/radeonsoftware/adrenalin/enhanced-sync/
     
    Last edited: Apr 5, 2018
  13. yasamoka

    yasamoka Ancient Guru

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    For f***'s sake.

    When are we going to finally agree that AMD's PR doesn't ALWAYS get it right ...?

    This is not true. Try this on any FreeSync monitor: limit your framerate just slightly below your monitor's refresh rate or try a game with a built-in hard / soft framerate cap. You will notice that even though the framerate is just slightly below the refresh rate, you will get tearing. This is because V-Sync on BOTH G-Sync and FreeSync also enables frametime conpensation in order to align a frame that is ever so slightly faster than the minimum frametime to the scanout. This does not add any latency other than what is inherent to the slight delay in order for the alignment to be possible. Tearing can get below this latency slightly (imperceptibly) by "defeating the scanout", as Mark Rejhon of BlurBusters terms it, but at the expense of tearing and partial frame information. This, again, for the zillionth time, applies to BOTH G-Sync and FreeSync and ANYONE who owns any such monitor should be able to test and report back, repeatedly. If you still are hellbent on not believing this then go and try it on any such monitor yourself ...

    That's correct. Additionally, the highest refresh rate should be used in order to reduce V-Sync stutter.

    Not true unless he simply means extra frames will NOT be rendered ... otherwise, if he means what the terms signify semantically, then there is no "rejection" going on. The CPU will simply force a wait before it requests another frame to be rendered. You WILL get extra latency, almost equivalent to V-Sync latency. AGAIN: you can try this yourself and you will notice, extremely easily, the added latency, particularly at 60Hz.

    It is not possible to reject frames and maintain smoothness since their frames are each rendered according to a moving animation timer, so any missing frames WILL show stutter and unevenness due to the very nature of such discrete frame rendering.

    That is correct. The goal with both G-Sync and FreeSync is to KEEP the game in that window, which is what the frame cap is there for. More on that later ...

    Correct. However, this gives the illusion that FreeSync with V-Sync on would give higher input latency. That would be true ONLY if you let the framerate hit the refresh rate. If you keep it below, the input latency is the same as long as frametimes aren't sporadically short enough to defeat the scanout. In those scenarios, you would see tearing with V-Sync off, no tearing with V-Sync on DESPITE the framerate apparently being within the G-Sync / FreeSync window.

    Furthermore, the difference in input latency between very high framerate with V-Sync off and framerate JUST below the refresh rate are VERY minor. This is theoretically valid as well as practically - you cannot perceive the difference easily at all unless the game engine behaves differently at different framerates. If you're a professional, you could get minor overshoot / undershoot from the miniscule difference in input latency, but as far as consciously perceiving it, good luck with that.

    Correct.


    Nope. Explained why earlier.

    Correct.

    Only problem is that no one recommends frame caps via FRTC. RivaTuner is the best for frame caps. Also, what sort of interference is he talking about? Both work together perfectly. The only way to have the smoothest experience with G-Sync / FreeSync monitors at high framerates that can exceed the monitor's refresh rate without the increase in input latency associated with V-Sync ON is by capping your framerate. Again ... try someone's FreeSync monitor and see for yourself.

    AND introduce higher input latency.

    Or for people who do not realize that neither Nvidia Inspector nor FRTC have trouble-free frame capping without increased input latency. RTSS is the way to go, again.

    NO. F*** NO. Worst advice ever. Whenever the framerate goes up, you lose the smoothness advantage of G-Sync / FreeSync as it is now possible for more than 1 frame to be rendered in a refresh interval and this means that anything other than the newest frame is dropped. ONLY if you have VERY high and CONSISTENT framerates would Enhanced Sync EVER be useful when you have a FreeSync monitor, and it STILL won't get you the smoothness of FreeSync unless the framerate is an exact perfect multiple of your refresh rate. Latency would still be higher than FreeSync + V-Sync ON + FPS cap since Enhanced Sync, like Fast Sync, is simply true triple buffering with a brand name.

    Can we let this die already? Or not?
     
  14. Chastity

    Chastity Ancient Guru

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    Why don't we just update the formula to something current:

    Chill + FreeSync = smooth gameplay, low latency, lower temps and power consumption It's a win all around.
     
  15. sverek

    sverek Ancient Guru

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    what is chill?
     

  16. sheep

    sheep New Member

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    I would still like to see some latency measurements for Chill being used as an FPS cap. It's probably placebo but to me it feels like it has more delay than built in limiters. Maybe even more than RTSS.
     
  17. RealNC

    RealNC Ancient Guru

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    If Chill can be used to do a 24FPS cap, then you can test it yourself without special equipment. Use a 24FPS cap in Chill and set RTSS to 0FPS (which disables its limiter.) Start a game, preferably one that has a software mouse cursor (like Fallout 4.) Move the mouse around. Alt+tab to RTSS and set a 23FPS limit. If the in-game mouse cursor doesn't feel any different, then that means Chill doesn't add input lag.

    Doing this test using NVidia's limiter reveals a big input lag penalty (the mouse cursor feels as floaty as a boat prior to enabling the RTSS limiter.)
     
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  18. Meccs

    Meccs Active Member

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    So if I understand this correct:
    If I have a 70Hz FreeSync Monitor and the frame rate of a game fluctuates between 60 and 80 fps, the best thing for low latency and no tearing would be: FreeSync on, Vsync on and cap the frame rate at 67/68 fps with RTSS? Since the fps will never go above 67/68 because of the RTSS limit, Vsync would never be enabled? And since the fps doesn't go out of the FreeSync range on the low end, FreeSync would be on all the time.
     
    Last edited: Jun 2, 2018
  19. yasamoka

    yasamoka Ancient Guru

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    68FPS.
     
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  20. Meccs

    Meccs Active Member

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    Yes, thanks I just edited my post and corrected that.

    Thank you, finally someone that could clear that up. It is mainly an issue for lower Hz monitors since the FreeSync range is way smaller and you are more likely to go above the range. Still, AMD should make an effort to explain the optimal settings better.
     

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