What is causing stutter with a VRR screen below 60fps

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Squall1er
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What is causing stutter with a VRR screen below 60fps

Post by Squall1er » 31 May 2021, 11:52

Hello everyone

There is a thing that bother me and I don't understand it neither.

I'm using a Z35p for a couple of years now, great monitor, G-sync work fine with the recommandation of Blur Buster.
I understand how G-sync and V-sync work. I consider myself having a good knowledge on display and how everything about it work.

But why, with G-sync enable, everytime I hit below 60fps I got stutter. No tearing at all, but below 60fps it work like i'm using software V-sync, got stutter and fall to 30fps.

It's easy to fix that by having allways more than 60fps but some games (hello Cyberpunk) are a pain in the ass and get down around 50/55fps.

So now i'm pissed about it.

Am I not supposed to have a stutter free experience with G-sync enable? What cause this stutter, and why at 59fps and not at 119fps?

Thank you

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Re: What is causing stutter with a VRR screen below 60fps

Post by RealNC » 01 Jun 2021, 07:28

Is it happening in all games? Stutter like this usually implies that the game is CPU-bound rather than GPU-bound. Unless you're playing in windowed mode with g-sync. Then stutter also occurs when GPU-bound.
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Re: What is causing stutter with a VRR screen below 60fps

Post by Squall1er » 01 Jun 2021, 13:23

Yes, everytime a game is too badly coded and even with my setup it drop below 60fps it's happening.

I'm playing in full screen but I used to play in windowed fullscreen and it was the same.

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Re: What is causing stutter with a VRR screen below 60fps

Post by Chief Blur Buster » 01 Jun 2021, 17:49

Is this regular stutter like the low-framerate UFOs at bottom of www.testufo.com#count=4 ? Unfixable.
Or is this erratic stutter like www.testufo.com/stutter ? Sometimes fixable.

If erratic stutter, how big is your VRR range?
If your monitor is only 144Hz, there can be visible LFC erratic-stutter too.
LFC erratic-stutter is more invisible on monitors with wide VRR ranges, e.g. 48Hz-240Hz VRR.

You can improve low-framerate "regular stutter" somewhat by enabling GPU motion blur again in the Cyberpunk menus. This will make motion even more blurry but it will mask some of the stutter. Anything ~60fps and up, I recommend disabling GPU motion blur effects.
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Re: What is causing stutter with a VRR screen below 60fps

Post by Squall1er » 04 Jun 2021, 15:35

In fact, it's not really stuttering

It'smore it feel like, everthing is smooth at 60fps and above and immediatly at 59fps it feel laggy.

I mean, you don't notice a difference between 62 and 65fps, but here I clearly notice everytime I hit 59fps

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Re: What is causing stutter with a VRR screen below 60fps

Post by Squall1er » 23 Mar 2024, 08:12

Hello guys

I was thinking about that again while playing Cyberpunk, despite having a 7800x3D now I still got some moments where the GPU is not 100% usage... so sometime it got under 60fps.

So after those almost 3 years, it's still the same. Whenever I go under 60fps it become, it become laggy. I'm now running a AW3423DWF of course nothing change.

61 fps is totally fine (even i'm now use to more, like 70to90 usually) but 59fps is immedialty terrible. I shouldn't notice difference between 61 and 59fps, but there is a difference, a very noticable one

Is there something to do with 60hz behing the standard, or frametime or idk whatelse? Still a mystery

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Re: What is causing stutter with a VRR screen below 60fps

Post by jorimt » 23 Mar 2024, 19:42

Squall1er wrote:
04 Jun 2021, 15:35
In fact, it's not really stuttering

It'smore it feel like, everthing is smooth at 60fps and above and immediatly at 59fps it feel laggy.

I mean, you don't notice a difference between 62 and 65fps, but here I clearly notice everytime I hit 59fps
In my experience, there is a subtle, but notable drop in perceived fluidity from 60+ FPS to 59 FPS (and below) at 60Hz, regardless of the game (or configuration, be it monitor, system components, etc), with or without CPU/GPU limitation or G-SYNC.

It's just how sub-60Hz feels (and has always felt, especially when synced), and since 59 FPS = 59Hz with G-SYNC, this feeling will remain.

G-SYNC does not make a lower frame/refresh rate feel higher, it merely prevents tearing artifacts for framerates within the refresh rate.
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Re: What is causing stutter with a VRR screen below 60fps

Post by RealNC » 24 Mar 2024, 05:38

Squall1er wrote:
23 Mar 2024, 08:12
So after those almost 3 years, it's still the same. Whenever I go under 60fps it become, it become laggy. I'm now running a AW3423DWF of course nothing change.
Even with Nvidia Reflex?
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Re: What is causing stutter with a VRR screen below 60fps

Post by Squall1er » 26 Mar 2024, 16:43

jorimt wrote:
23 Mar 2024, 19:42
Squall1er wrote:
04 Jun 2021, 15:35
In fact, it's not really stuttering

It'smore it feel like, everthing is smooth at 60fps and above and immediatly at 59fps it feel laggy.

I mean, you don't notice a difference between 62 and 65fps, but here I clearly notice everytime I hit 59fps
In my experience, there is a subtle, but notable drop in perceived fluidity from 60+ FPS to 59 FPS (and below) at 60Hz, regardless of the game (or configuration, be it monitor, system components, etc), with or without CPU/GPU limitation or G-SYNC.

It's just how sub-60Hz feels (and has always felt, especially when synced), and since 59 FPS = 59Hz with G-SYNC, this feeling will remain.

G-SYNC does not make a lower frame/refresh rate feel higher, it merely prevents tearing artifacts for framerates within the refresh rate.
So you feel exactly the same as me. And you have no explanation for this behavior.
And apparently since you know your subject, I guess no one will put a word on what is happening under 60fps

thank for you help

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Re: What is causing stutter with a VRR screen below 60fps

Post by jorimt » 26 Mar 2024, 17:41

Squall1er wrote:
26 Mar 2024, 16:43
So you feel exactly the same as me. And you have no explanation for this behavior.
I have an explanation, it's just not a satisfying one; 59 FPS/Hz isn't 60 FPS/Hz.

There are thresholds where perceived fluidity changes based on the frame/refresh rate, and some players are more sensitive to this than others, some not at all.

For instance, say you're playing a game with G-SYNC on a 240Hz monitor, and it fluctuates anywhere between 30 and 240 FPS at 240Hz. I can easily tell without any visible readouts the general framerate range I'm in, typically at 15, 25, 30, 45, 50-59, 60, 75, 85-100, 120+ FPS (with anything well above 120 FPS/Hz becoming less and less visually impactful, at least compared to 30 vs 60, or 60 vs 120), and I'm usually within a few frames of what I'm feeling when I do enable the readouts.

What causes this is the direct contrast between the varying frame/refresh rate in real-time.

It's much less noticeable if you play at a fixed framerate instead of letting the average framerate vary wildly. I.E. a 30 FPS console game is tolerable only if it's a consistent 30, but once you switch to 60, it's immediately intolerable and you can't imagine how you were playing at that framerate the entire time, and so on.

It's similar to the difference between trying to pick out subtle differences between two otherwise identical side-by-side image, or alternating between the two at will (one over the other); the latter makes any differences, no matter how small, obvious, whereas the former does not.
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Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48CX VR: Beyond, Quest 3, Reverb G2, Index OS: Windows 11 Pro Case: Fractal Design Torrent PSU: Seasonic PRIME TX-1000 MB: ASUS Z790 Hero CPU: Intel i9-13900k w/Noctua NH-U12A GPU: GIGABYTE RTX 4090 GAMING OC RAM: 32GB G.SKILL Trident Z5 DDR5 6400MHz CL32 SSDs: 2TB WD_BLACK SN850 (OS), 4TB WD_BLACK SN850X (Games) Keyboards: Wooting 60HE, Logitech G915 TKL Mice: Razer Viper Mini SE, Razer Viper 8kHz Sound: Creative Sound Blaster Katana V2 (speakers/amp/DAC), AFUL Performer 8 (IEMs)

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