G-sync Causing Weird Checkerboard-like Pixelation on screen

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag. List of G-SYNC Monitors.
Kaelib
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G-sync Causing Weird Checkerboard-like Pixelation on screen

Post by Kaelib » 25 Dec 2015, 11:36

Hi everyone,

As stated, My Gsync monitor is causing a very odd issue that I cant seem to find anywhere else online. Here is an album showing it happen and one other comparison image without it happening.

http://imgur.com/a/5H6g5
(first img its happening, second its not)

Basically, any time my gsync drops below 50fps, it causes this effect, and is happening in every game I own.

After some research on my end, I have yet to see anyone else with this issue, so I am guessing it may lie with my new monitor, and be a hardware issue, and may just need a RMA.

That said, it only happens with gsync on, With gsync off and I drop below 50fps, this problem does not occur.

Things I have Tried but no effect.
- Different Drivers
- Clean Driver installs
- Different OS
- Turning off all overclocking and apps running in the background
- Taking ingame screenshots to test if it is only on monitor display (it is only happening externally on monitor, not in game)
-underclocking video card

Nothing seems to be affecting it, and at this point, I am at a loss.

Specs for monitor and video card are
- monitor: AOC 2460PG
- Video Card: 970 4GD5T OC

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lexlazootin
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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by lexlazootin » 28 Dec 2015, 00:54

Yea, this is common and nothing is wrong.

I'm 100% guessing but i think it's cause when the fps gets too low the frames have to double to ensure that there is no damage to the panel at lower refresh rates. These cheap panels also are only 6bit, so they will dither between two colours at higher refresh rates to display a third colour to compensate.

But at lower refresh rates the dithering stops as too not be super obvious flashing or maybe because they couldn't get it to work with Gsync?

Like i said, i don't know but i think this might be right.

Kaelib
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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by Kaelib » 29 Dec 2015, 01:12

I don't think this is correct on both your points.

1. My monitor is 8-bit, 16.7 million Colors. Confirmed this in both nvidia control panel and on the monitor's spec sheet (I believe older TN panels were 6-bit, but that is no longer the case with the gsync versions).

2. This is only occurring in Gsync lower frames, but not happening in normal play at low frames with Gsync turned off. The doubling of frames will happen without Gsync on, as 144hz refresh tries to match 40 frames, it will need to either tear the frame or display it 2-3 times before refreshing. With Gsync, it will lock my refresh rate to the frame, never needing or even able to display another frame until the video card is ready (this could leading to flashing if at zero frames, but not during normal play). That being said, under 30fps, the drawing of 2 frames does occur on Gsync modules, but I am only talking 40-50fps, where it should be functioning normally.

I contacted AOC about this issue, and they recommend a RMA, so I am just going to do that and hope the next one is not also faulty. If it is, I will just up my game to a Rog Swift.

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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by RealNC » 29 Dec 2015, 12:05

If you get that with g-sync at 50FPS, you can try to confirm it by creating a 50Hz mode in CRU. (Google "toastyx cru"). If you also get that problem when you switch to 50Hz (g-sync off), then your monitor is either defective, or the panel is... well, crappy :-P
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lexlazootin
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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by lexlazootin » 30 Dec 2015, 05:14

Kaelib wrote: 1. My monitor is 8-bit, 16.7 million Colors. Confirmed this in both nvidia control panel and on the monitor's spec sheet (I believe older TN panels were 6-bit, but that is no longer the case with the gsync versions).
Yea, it's 8bit but it's not real 8bit because it's 6bit with dithering to achieve 8bit.

My monitor is a XL2420G gsync monitor and it's 6bit with dithering but in the driver it says 8bit: http://i.imgur.com/X0wIVII.png

If you google around you will see everywhere that your monitor is 6bit with dithering.
Kaelib wrote:drawing of 2 frames does occur on Gsync modules, but I am only talking 40-50fps, where it should be functioning normally.
I did a quick test. i loaded up CS:S and i switched frame rates till the super obvious dithering occurred and it happen at 55fps.
Kaelib wrote:I contacted AOC about this issue, and they recommend a RMA, so I am just going to do that and hope the next one is not also faulty. If it is, I will just up my game to a Rog Swift.
I remember i asked SteelSeries why my Kinzu was jumping pixels at 1800dpi and like in the second demonstration of this img here:

https://forum.lowyat.net/uploads/attach ... 789017.jpg

they told me too send it in for a RMA, i just chose not to use that DPI setting. Later i found out that every Kinzu did that and the guy i was talking to was a compete fuckwit.

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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by Aeon » 28 Jul 2017, 15:02

Hey, I have exactly same behavior with my AOC g2460pg. Looks like its normal for that "cheap" panel.
I can actually see grid when fps is anywhere below 60 fps. At 55 grid is slightly visible, at 30 its very distracting.
How your story ends? Just curious.
I'm not gonna RMA it, problem isnt really significant for me since i'm not gonna play much under 60 fps anyway. Only seeing grid in loading screens and occasional drops.
Also its freaking hard to find g-sync monitors here, that costs less than my 2 month salary, lol. Stuck with AOC.

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jorimt
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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by jorimt » 28 Jul 2017, 16:19

@Kaelib I believe that is a form of pixel inversion, which is common on TN panel types, and likely not caused directly by G-SYNC or the minimum refresh range (which starts at <36Hz/fps on most 144Hz panels).

It could be exacerbated by G-SYNC matching the refresh rate to the framerate at sub 60 FPS though.

Have you tried this motion tests on your display?
http://testufo.com/#test=inversion
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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by Aeon » 29 Jul 2017, 01:53

@jorimt yes, I tried and it looks pretty colorfull. Two lines are green, other one is pure purple :)
Some of my tests:
-with G-SYNC ON 144hz even under 36 fps (I tried 10-60 range) image is full of pixelation
-with G-SYNC OFF 144hz its completly clear image at any given fps. Imposiblew to see any sigh of pixelation.
-with G-SYNC ON and 60hz, 120hz - grid is still here.

It seems only g-sync causes a problem.

Not yet tested:
-G-SYNC OFF, 60hz, V-SYNC ON and different fps caps.
-G-SYNC ON and custom hz like 40hz + different fps caps

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jorimt
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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by jorimt » 29 Jul 2017, 09:25

Yes, you'd have to test non-G-SYNC by forcing a custom Hz level. G-SYNC may be exposing the issue where non-G-SYNC cannot, as G-SYNC adjusts the refresh rate to the framerate, and non-G-SYNC remains at the max set refresh rate at all times, no matter the framerate.

The pixel inversion patterns, depending on the panel, may be more evident at lower refresh rates (not framerates). This wouldn't be the fault of G-SYNC per say, just a side effect of its functionality that exposes the fault of the panel type.

This is not an issue common on IPS panels, mind you. It is usually only a weakness seen on TN panels.
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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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Re: G-sync Causing Weird Checkerboard-like Pixelation on scr

Post by Chief Blur Buster » 29 Jul 2017, 09:49

jorimt is right here.

(That said, I've seen it to a lesser extent on IPS and VA -- it's just worst on certain TN panels).

Fluctuating variable refresh rates can amplify inversion artifacts.

LCD inversion (the pixel electricity balancing technology, explained at Techmind) should be invisible, but it can generate artifacts ("LCD inversion artifacts") like checkerboard patterning, or green/purple distortions, etc. Some monitors do a better job than others.

Variable refresh rate simply adds a new variable to the equation -- as the refresh rate goes up/down, the inversion artifacts (if they're already bad) can be further amplified by the varyness of the refresh rate, yes.

Fix? Sometimes it's a panel lottery, sometimes it's unsolvable (for that particular panel), and sometimes you just have to switch to a different technology (e.g. IPS GSYNC monitors have less inversion artifacts than TN GSYNC monitors -- see List of GSYNC Monitors.)

However, there MAY be an inversion flaw if GSYNC 120fps@120Hz looks worse than normal 120fps@120Hz. Can you play a full-framerate GSYNC game such as Half Life or Counterstrike, at the full capped-out GSYNC 120fps -- and let me know if the exact same framerates looks worse? (Keep framerates high -- 120fps nonstop). That would rule out the "varyness" factor, and confirm a possible logic flaw with the inversion that might need addressing (e.g. firmware upgrade, RMA, etc)
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