PG258Q Pixel Inversion

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Akaranir
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PG258Q Pixel Inversion

Post by Akaranir » 28 Jul 2017, 15:23

Hello,

I just bought the PG258Q (my first monitor 144hz and above) and i really struggle with the blur that creates itself in motion because of the highlighting of the pixels i suppose to be "pixel inversion".

It's so boring that i find myself stopping to move to see better ...
Is it the gsync monitors that have this problem ? Or the 120/144hz monitors and more ?
Is this normal or is my monitor broken?

Do you have monitors names 120/144 hz that do not have pixel inversion problem ? (Even if they do not have gsync or ulmb)

Thanks.

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RealNC
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Re: PG258Q Pixel Inversion

Post by RealNC » 28 Jul 2017, 17:09

Does it help if you turn down or completely turn off overdrive in the monitor's OSD? It's the "OD" setting in the "Image" menu. Try all three settings (Off, Normal, Extreme.)
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Akaranir
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Re: PG258Q Pixel Inversion

Post by Akaranir » 29 Jul 2017, 01:49

It does not change anything, even by changing the frequency, ulmb or gsync.

open
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Re: PG258Q Pixel Inversion

Post by open » 29 Jul 2017, 20:29

I have the same screen. If you are talking about the vertical lines, I only notice them when:
1)I am using ulmb and watching fast motion sometimes I will notice
2)When I am using 240hz gsync and the framerate of the game drops below the lower gsync limit (seems like around 45 fps)
3)I feel like I have noticed in rare occasions when my computer is unresponsive/loading something.

With case #2 I also see a flickering of the screen that does not happen any other time.

Are you talking about the vertical lines?

Perhaps try using a different computer as for me this only happens in certain states of the computer I am using.

It may be better or worse on a monitor by monitor basis.

open
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Re: PG258Q Pixel Inversion

Post by open » 29 Jul 2017, 21:27

ON A PERHAPS RELATED NOTE. This is a 6bit + FRC monitor. How is the FRC implemented? Since we need 2 extra bits of depth, there would need to be at least 4 frames in each temporal pattern that makes a color. Are the frames happening on each normal refresh? For example if one colors least significant bits are 01, it would need 3 frames of the darker color and 1 frame of the brighter color to average a 1/4 intensity of 100 (still binary) color. Do these frames happen at 240hz or do they happen faster? I have heard that FRC uses inversion patterns like this in its implementation. Perhaps this is why the lines are noticeable during strobing modes where there is motion. But I don't know how FRC really works. Maybe it has some way of regulating the voltages at above 240hz as to avoid being noticed. When I look up FRC there is not alot of information. Even if it was regulating voltages up and down at above 240hz it may be possible to notice during the right situations. Like when pixel response times differed greatly due to slight voltage differences causing the alternation to leave visible artifacts during animation and revealing the inversion pattern.

anothergol
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Re: PG258Q Pixel Inversion

Post by anothergol » 29 Jul 2017, 23:34

While I have no clue (well I do now, but I don't fully understand it) what produces pixel inversion artefacts, it's most likely not FRC because the Samsung CFG73 I tested it with, gave horrible results and it's normally truly 8bit.

I'm wondering about how much these artefacts are annoying in games & movies, though. Probably not much in 3D games or movies, if at all. But on the dithered background of a scrolling web page, or in a scrolling game with pixel art, it's just horrible.

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lexlazootin
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Re: PG258Q Pixel Inversion

Post by lexlazootin » 30 Jul 2017, 00:38

Yep, i have the Acer and G-Sync and i'm pretty sure it's just how the panel works. I don't have a solution but i see it too, especially at lower hz.

open
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Re: PG258Q Pixel Inversion

Post by open » 30 Jul 2017, 17:28

So from the VERY LIMITED info I can find about FRC:
I found multiple instances of people saying that it works at 30hz and produces a 30hz flicker including the wikipedia page on frame rate control. I'm assuming that they are using 120hz monitors as the standard in this case. 240hz would produce a 60hz or 120hz flicker depending on if the least significant bit is 1 or 0. This page also says that it works with each "new frame". Also there are many instances of people saying that FRC creates inversion patterns. The inversion patterns would prevent pixels on sections of the screen from flickering at the same time and perhaps stop it from being noticed through brightness on a macro level.

Given the information and the context that this happens in, it is VERY likely to be the implementation of FRC. The conditions that this would be noticed in are the exact conditions that we see it happening in. And result is exactly as would be caused by FRC with an inversion pattern.

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Chief Blur Buster
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Re: PG258Q Pixel Inversion

Post by Chief Blur Buster » 30 Jul 2017, 17:33

Yes, FRC dithering pattern (supposed to be invisible) can have interactions with the inversion pattern (supposed to be invisible).

It can creating some interesting visible inversion patterns, especially at very low refresh rates on certain colors (e.g. Lagom Black Level, or certain shades at Lagom Contrast).

The lower the refresh rate, the easier it is to see FRC limitations. The emergence of VRR monitors means you can often find a monitor that can refresh as low as 30 Hz (sometimes less, e.g. 24Hz), allowing FRC and/or inversion to run in "slow-motion", that can have amplified visibility of either FRC or inverison (and/or artifacts from the interaction of the two).
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Akaranir
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Re: PG258Q Pixel Inversion

Post by Akaranir » 31 Jul 2017, 14:23

So are only the Gsync monitors that have pixel inversion/vertical lines ?

If i take a monitor like the XL2540 am i sure that there will not be this problem ?
Because on games at 60/144 hz it's horrible.

And last question why does Gsync consume as much resources ? When i activate gsync i easily lose 60/80 fps ...

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