Freesync (g-sync compatible) monitors flickering on 60fps games

Talk about AMD's FreeSync and VESA AdaptiveSync, which are variable refresh rate technologies. They also eliminate stutters, and eliminate tearing. List of FreeSync Monitors.
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diakou
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Joined: 09 Aug 2020, 11:28

Freesync (g-sync compatible) monitors flickering on 60fps games

Post by diakou » 14 Nov 2020, 00:26

So Brawlhalla is a game that does not have exclusive fullscreen modes or a proper flip-model, it cannot be identified for G-Sync to work without using the fullscreen NVIDIA Control Panel trick and then going into NVIDIA Profile Inspector to then enable application mode fullscreen + windowed and global mode fullscreen + windowed.

However - this so far seems to not work on almost any g-sync compatible 240hz or 144hz (freesync) monitors with NVIDIA cards, irregardless of driver versions or editing the VRR Range to be lower (30-38-48) however I have not tested with HIGHER VRR range yet. The reason why I suspect this to be a problem of VRR ranges is because 1) there are randomly at times, where it'll actually NOT flicker, but it's usually very short-lived like a minute or so. (this behavior replicated on 4 different monitors, I have a lot of friends to test stuff with) and whenever g-sync is obviously active with or without flicker, the game is incredibly smooth (inputlag, as v-sync is forced in that game and this seems to break the compositor delays to an extent, giving lower lag and smoothness.)

I have confirmed it to be flicker-free with a g-sync module, a 240hz and a 360hz. The 360hz has a VRR range of 1-360, so this is essentially why I believe it to be a problem of the VRR range.

Any tips for what to do to possibly make the flickers dissappear? I have tried a bunch of options, but in general, this entire thing seems like black magic and info is ridiculously limited. Everyone has a weird "trick" that works for them, but seems to not be universal whatsoever for fixing flicker and freesync. I have a lot of people who'd benefit from making this work, but it seems impossible, the next attempt will be higher VRR ranges, but I'm not sure what ranges would be safe. I'm thinking something like 100-240 and not 48-240 etc might make it flickerfree. Would appreciate some tips.

diakou
Posts: 83
Joined: 09 Aug 2020, 11:28

Re: Freesync (g-sync compatible) monitors flickering on 60fps games

Post by diakou » 28 Dec 2020, 03:52

Update;

Editing VRR minimum range from [30, or 48, or 40] to 55-65 (65 in this case) makes a 240Hz freesync monitor run perfectly fine in a 60FPS locked game with no flicker. I assume it's LFC shenaningans.

Not sure how many people this will help, but both the VG259QM/279QM and the Omen X 25f has success with increasing the VRR minimum range to get G-Sync/Freesync to work flawlessly @ 240Hz+ ranges for a 60FPS locked game(side-note, it also helped with making CoD Warzone flicker-free as well.) It's an interesting problem to have truly - but I am always astounded by how great a 60FPS game (especially capped games / forced v sync on games) runs when it's able to G-Sync at 240Hz+

Ridiculously low inputlag and incredibly smooth gameplay, just missing a ULMB + G-Sync option that doesn't suck and nirvana may be close.

Personally I'll see if there exists a method to utilize a 60Hz strobe through "CRU" hack with the AW2521H but take it a step further and see if I can get G-Sync working at 360HZ at the same time - now that would be something. A hacky ELMB-Sync ;P

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Chief Blur Buster
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Re: Freesync (g-sync compatible) monitors flickering on 60fps games

Post by Chief Blur Buster » 01 Jan 2021, 16:17

diakou wrote:
28 Dec 2020, 03:52
Update;

Editing VRR minimum range from [30, or 48, or 40] to 55-65 (65 in this case) makes a 240Hz freesync monitor run perfectly fine in a 60FPS locked game with no flicker. I assume it's LFC shenaningans.

Not sure how many people this will help, but both the VG259QM/279QM and the Omen X 25f has success with increasing the VRR minimum range to get G-Sync/Freesync to work flawlessly @ 240Hz+ ranges for a 60FPS locked game(side-note, it also helped with making CoD Warzone flicker-free as well.) It's an interesting problem to have truly - but I am always astounded by how great a 60FPS game (especially capped games / forced v sync on games) runs when it's able to G-Sync at 240Hz+

Ridiculously low inputlag and incredibly smooth gameplay, just missing a ULMB + G-Sync option that doesn't suck and nirvana may be close.

Personally I'll see if there exists a method to utilize a 60Hz strobe through "CRU" hack with the AW2521H but take it a step further and see if I can get G-Sync working at 360HZ at the same time - now that would be something. A hacky ELMB-Sync ;P
It's definitely "LFC quirks".

Blur Busters Now Recommends Higher LFC Limits For 240Hz+ FreeSync Monitors

Even for monitors where there's no "55Hz Bug".

I now recommend higher LFC numbers for 240Hz+ FreeSync monitors, such as 55fps or 65fps because LFC stutter is a non-issue at high VRR ranges. 1/48sec is 20.8 milliseconds, and a "LFC miss" is a halftime of max Hz (0.5/240sec) = average 2ms stutter. A 2ms stutter on a 20.8ms frametime is invisible in low frame rate content, meaning 48 Hz is useless compared to the better-quality 65 Hz min-Hz LFC.

TL;DR: A higher LFC limit is nicer looking on 240Hz, 280Hz and 360Hz monitors. LFC becomes indistinguishable from native Hz when you have ultra-fast scanout max-Hz, so "Repeat-refresh collisions with original-refresh-ready events" are extremely brief.
Chief Blur Buster wrote:
jorimt wrote:
23 Nov 2020, 14:26
You saved me the trouble of finishing my in-progress reply.

This is pretty much exactly what I was trying to suggest. Again, I only posed it as a theory. I wasn't suggesting (and wasn't even sure if) it was actually practical. It sounds like there would certainly be some gotchas and trade-offs involved.
Oh, then that's what you meant. Well, good suggestion!
Unfortunately, I have heard from multiple channels they've tried that trick and panels are too imperfect to make it the lesser of pick-poison.

Fortunately, LFC stutter falls below the noise floor for ultrawide VRR ranges like the 360Hz ASUS whose refresh rate range is ginormous.

LFC at 20fps for a 50ms frametime, with a 1/360sec scanout, is only 2.8 milliseconds delay to a 50ms frametime. That stutter is generally completely hidden in the motionblur of low framerates. All repeat-refresh mispredicts on a 360Hz monitor (in casual random tests) have shown them to be invisible thanks to the ginormous VRR range (low Hz versus ultrafast scanout).

Even 1000Hz mouse microstutter is starging to be more visible than a LFC mispredict on a monitors whose VRR range is ginormously wide (approaching 10:1 max:min Hz). LFC ceases to be poison at that stage.

One can prefer native VRR range behavior to be closer to 70Hz-360Hz, since 30fps@60Hz has cleaner GtG behaviours than 30fps@30Hz and less GtG-derived faint flicker at sudden framerate changes (like bringing up a menu and disappearing it). And you avoid low-frequency inversion artifacts if there are any temporally occuring (faint shallow-cycle flickering inversion artifacts disappearing above flicker fusion threshold because of a higher minimum Hz).

When LFC ceases to be poison, it's favourable to raise LFC limit higher to erase other poisons.
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gunner7
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Joined: 15 Oct 2020, 14:48

Re: Freesync (g-sync compatible) monitors flickering on 60fps games

Post by gunner7 » 01 Jan 2021, 16:32

I had a question if you don't mind regarding Freesync - for competitive play, should I turn off Freesync playing games where I get pretty consistent 120fps on the Xbox series X, maybe dipping to 110 once in a while? From my research on here, I would get better input lag with turning VRR OFF? My monitor is 144hz Freesync Premium Pro.

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