Strange artifacts (dots)

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EvolutionBG
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Strange artifacts (dots)

Post by EvolutionBG » 09 Dec 2023, 11:12

Hello, I recently got a Samsung ViewFinity S6 (ls27a600uuuxen) and these strange artifacts seems like are appearing rather random.
My question what is the origin of such artifacts, could that be the GPU (although it doesn't do that on the other monitors), the cable?
I'm using the original HDMI cable which came with the monitor. At the moment it stopped showing them, driving me crazy, because I can't reproduce them. Thanks.
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Chief Blur Buster
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Re: Strange artifacts (lines and dots)

Post by Chief Blur Buster » 09 Dec 2023, 12:35

Probably LCD inversion artifacts that appear during motion of solid colors. Some LCDs are prone to them.

They generally chessboard textures, vertical lines or horizontal lines.

P.S. You can capture those artifacts better with a "pursuit camera" (enduser method = handwave smartphone in sync with motion)


EDIT: I see you edited your post; now I understand better. New reply at bottom.
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Re: Strange artifacts (lines and dots)

Post by EvolutionBG » 09 Dec 2023, 12:45

Sorry, maybe I wasn't clear - it doesn't have visible LCD inversion artifacts (I know when I see them). Maybe it's because of the camera.
I'm talking about the little dots: It doesn't seem to show them at 60Hz. Only at the default 75Hz option.
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Re: Strange artifacts (dots)

Post by EvolutionBG » 10 Dec 2023, 17:40

Hello again, I've tried with a DisplayPort cable (new one) - the issue still persist, it's showing more often when the monitor is set at 74.970 Hz (the default value of HDMI port according to Custom Resolution Utility 1.5.2). So far it hasn't showed at 74.998 Hz (the default value of DisplayPort).
It hasn't showed at 74.000 Hz either (HDMI / DisplayPort).

When I manually set it to 74.970 Hz using the DisplayPort cable - the dots reappeared again.

I think the problem is not with cables, but the monitor itself sadly.

I'm wondering if I should return it...?

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Re: Strange artifacts (dots)

Post by Chief Blur Buster » 14 Dec 2023, 01:07

Oh! Thank you for highlighting this better. That's definitely not LCD inversion, and that's definitely not video cable.

This specific category of clustered glitch is typically framebuffer memory behavior --is never the cable; I would not 100% confirm monitor either.

- This may be a GPU RAM defect;
- This may be a monitor-overclocking defect;
- Etc.

But here, I'd think it's the monitor, yes.

A framebuffer memory "cluster of glitches" corruption is usually either in the framebuffer on the GPU, or in the frame buffer in the monitor (the refresh cycle buffer). A lot of it is benign (like "CGA snow").

It's my understanding that this monitor you have is a fixed-Hz monitor (without VRR). Fixed Hz monitors are sometimes extremely picky about refresh rates before glitching, so using a refresh rate that behaves better, can solve the problem.

If it disappears at 75Hz, you're probably OK. It's /usually/ harmless, especially if the display is not VRR-compatible. You could also try to permanently turn on/off VRR and see if it works better. Monitors have had a history of glitching weirdly at unexpected refresh rates (whether fixed Hz or diferent VRR maximum Hz). Even 74.9fps with a better-tuned VRR max of ~75.000, can become better than 74.9Hz native, because of the way scalers/TCONs are designed. It's not always the case, but I've seen this type of thing happen -- sometimes it's a memory wait-state glitch or a monitor framebuffer DRAM refresh glitch due to unexpected clockspeeds etc. Like a modern-day equivalent of 1980s "CGA snow" effect.

If it bothers you that much -- you may have to consider another monitor. While you're at it, a higher refresh rate (120-240Hz) is still great for productivity, even if you never game. Dell recently added 120Hz to one of their office monitors, and many Mac's now come with 120Hz as high-mainstream standard. And FreeSync/GSYNC performs better when min,max Hz is a 2.5x difference. (e.g. 48-120Hz VRR is considered the minimum range I recommend if you ever use VRR -- because even 50-70fps VRR is much smoother when Vrr(Max) is 120Hz).

However, if you never see it at a new custom refresh rate, I think you've possibly fixed your problem. Don't waste time on cables anymore -- I'd put my money on the monitor framebuffer glitching occasionally (etc) -- but I have almost never encountered a completely bug-free monitor. If you completely fixed your problem via a custom 75Hz mode, I would just cease to worry about it.

Don't forget to check for firmware updates that might fix this problem; your monitor latest firmware would be Version 1014.0 0.88 released by Samsung on Nov 29. 2023, according to Samsung's Latin America website. Keep in mind that the chips running inside a 2020s monitor is more powerful than a year 2000s computer!!! Are you running the latest monitor firmware?
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Re: Strange artifacts (dots)

Post by EvolutionBG » 14 Dec 2023, 16:51

Hello and thanks for the reply.

Actually the monitor has FreeSync (48-75 Hz) and it's working fine with my GTX 1650 Super (with the exception of the range - 52-75 Hz and it's working only over DP). In more demanding games I like to turn off vsync and limit the FPS in-game or with RivaTuner Statistics Server to 60FPS to eliminate the tearing with lower input lag (not very low, but lower than vsync on).

I can confirm it is not my PC, because right now I have two monitors plugged in and working side by side (Samsung showing the dots) and the Dell S2721DS (FreeSync 75 Hz monitor) doesn't show any of that at the exact same refresh rate.
Chief Blur Buster wrote:
14 Dec 2023, 01:07
Dell recently added 120Hz to one of their office monitors, and many Mac's now come with 120Hz as high-mainstream standard. And FreeSync/GSYNC performs better when min,max Hz is a 2.5x difference. (e.g. 48-120Hz VRR is considered the minimum range I recommend if you ever use VRR -- because even 50-70fps VRR is much smoother when Vrr(Max) is 120Hz).
Thank you for that information, I will definitely look into it! If it doesn't have visible LCD inversion with reasonable IPS glow and good contrast (it says 2000:1 IPS black, which is great). Too bad it looks like it doesn't have FreeSync.
Chief Blur Buster wrote:
14 Dec 2023, 01:07
You could also try to permanently turn on/off VRR and see if it works better.
It seems like it doesn't matter if it's on or off.
Chief Blur Buster wrote:
14 Dec 2023, 01:07
However, if you never see it at a new custom refresh rate, I think you've possibly fixed your problem. Don't waste time on cables anymore -- I'd put my money on the monitor framebuffer glitching occasionally (etc) -- but I have almost never encountered a completely bug-free monitor. If you completely fixed your problem via a custom 75Hz mode, I would just cease to worry about it.
It hasn't showed them for a 3 days now, so I guess it's fixed (not custom refresh rate, it's the default DisplayPort one, which is different than the HDMI one). I had to buy a DP cable, because the monitor came only with an HDMI.
Chief Blur Buster wrote:
14 Dec 2023, 01:07
Are you running the latest monitor firmware?
I'm running 1013.0, but I asked Samsung what is new in 1014.0, their response:
Samsung wrote:Thank you for your message!
Major Firmware updates available for our monitor models directly tie security patching and product compatibility support to newer technologies and media.
Also I'm not sure if I can return the monitor if I update the firmware.

Now I might return this Samsung, really want to try the Dell U2724D... but I might need to wait for the RTings review...

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