Every monitor is bad: Bought a Koorui 27E3QK 1440p 240hz - Has slight PWM-like effects

[r0ach]

This monitor has excellent speed and pretty decent image quality. I would have kept it but after using it for several hours you start to notice an uncomfortable PWM-like feeling in your eyes building up. It takes an hour or two before you start to notice it so it's not as big of a problem as some other panels but it's there. I don't experience issues like this on Samsung VA panels such as Odyssey G3.

I bought a refurb Acer XV252Q 390hz panel and this problem was much worse on that panel. It feels like this issue exists on all these new monitors claiming to not have PWM but it seems they have a flicker rate problem or other issue with cheap race to the bottom backlighting/LED's.

Anyone know of a 1440p 240hz monitor without this issue? Do any actually exist? Potential ones I haven't tried:

MSI G274QPX (slow response, too high min brightness 121cdm2)
Acer XV272U W2bmiiprx
Acer KG271U Xbmiipx
Asus XG27AQMR
Asus VG27AQML1A (pretty sure BOE panel so probably avoid)
Innocn 27G1S
GIGABYTE M27Q X (sharp panel? so probably avoid. Have had bad experiences with Sharp panels in the past)

[r0ach]

Asus XG27AQMR on the way now for next round of monitor eyestrain roulette. I've seen people claim an Acer 300hz model supposedly uses the same panel and has eyestrain but from what I've noticed, it seems like there's more complaints about eyestrain from Acers than any other brand that exists.

I thought AU Optronics shipped these panels with backlights already fused to them, but apparently that's not the case so it might be possible there can be eyestrain from one vendor and not the other even using the same panel. Before anyone talks about red phosphors and quantum dots and everything else, I'm not convinced there's an inherent problem with wide gamut or "KSF red phospher" panels for several reasons.

People claimed eyestrain on LG panels such as 27GN850 was due to nano ips wide gamut, but even on their 27GN750-B which is supposedly not nano IPS or wide gamut, this monitor was still less comfortable to look at and harder to focus on than older panels. This leads me to believe it's likely something else such as cheap, race to the bottom electronics powering the backlight causing the waveform to be jittery and causing PWM-like effects while reviewers claim no PWM is there.

Here's how I would rate eyestrain for monitors I've recently used from highest to lowest:

1 - The "Fire Legend" version of Acer Nitro XV252Q 24.5" 390hz (AU panel)
2 - Samsung Odyssey G4 27" 240hz 1080p IPS (think it uses BOE panel)
3 - Koorui 27E3QK 27" 1440p 240hz (pretty sure AU panel - weird effect on your eyes that makes you open them as wide open as possible while supposedly not having PWM)
4 - LG 27GN750-B 27" 1080p 240hz (LG panel - supposedly not wide gamut but has 113% SRGB???)
5 - Asus VG27AQ 27" 1440p 165hz (pretty much no eyestrain but monitor min brightness too high)
6 - Asus VG278Q 27" 1080p 144hz (pretty much no eyestrain but VA-level slow)
7 - Samsung Odyssey G3 27" 1080p 144hz (VA panel - pretty much no eyestrain but not quite as good to look at for fatigue as some older 60hz panels)
8 - The original 27" Apple Cinema Display LG Panel (an IGZO?) also sold in those Korean IPS Ebay monitors
9 - Samsung 27" 60hz PLS and TN panels

I've had good luck with IGZOs in the past - one of the easiest to look at displays is the 1st gen Ipad Air 1 LG IGZO - and XG27AQMR is also supposedly an IGZO, so hoping that benefits it in some manner.

[Sirius]

Asus VG27AQML1A (pretty sure BOE panel so probably avoid)

GOD FINALLY !

Finally a guy who complain about BOE and didn't like them.
Here is a tips : YES ! the VG27AQML1A have a BOE panel, i've had this one few month ago and it was simply horrible.
I've talk about this monitor but not in a proper post.

Pratically all recent IPS panel have a BOE panel, even the new batch of M27QX, they didn't use Sharp panel anymore ( idk why honestly ) but it is the same panel as the VG27AQML1A and it was like the Asus : HORRIBLE.

[r0ach]

Finally a guy who complain about BOE and didn't like them.

They started putting BOE's in Apple products and they're bad there too. I've used LG's before that were good for my eyes and others that caused problems, but I've never used a good BOE in any device ever. As for AU Optronics, they seemed to be fine before the wide gamut era, but now it seems these have eye issues too.

From what I understand, everything is going to be some variation of either KSF or quantum dot now, so it seems like you have to find which one annoys you the least. I'm still not convinced that eye problems are entirely due to these wide gamut implementations, though. I feel like there is a race to the bottom in cost cutting maybe affecting backlight stability because it seems like the cheap Acers have more complaints on these eyestrain issues than any other brand.

[Sirius]

Finally a guy who complain about BOE and didn't like them.

They started putting BOE's in Apple products and they're bad there too. I've used LG's before that were good for my eyes and others that caused problems, but I've never used a good BOE in any device ever. As for AU Optronics, they seemed to be fine before the wide gamut era, but now it seems these have eye issues too.

From what I understand, everything is going to be some variation of either KSF or quantum dot now, so it seems like you have to find which one annoys you the least. I'm still not convinced that eye problems are entirely due to these wide gamut implementations, though. I feel like there is a race to the bottom in cost cutting maybe affecting backlight stability because it seems like the cheap Acers have more complaints on these eyestrain issues than any other brand.

For me, there are only Innolux and AU Optronics that I like, in any case, I must have had 2 4K, 4 1440p and 1 1080p with BOE recently, they ALL were horrible, I'm not just talking about eye problems but even regarding colorimetry and motion clarity, like the M27QX and the VG27AQML1A, they were infamous.

I don't understand how Optimum Tech and Monitor Unboxed dare to recommend this kind of harmful and ultra bad screen, just because the monitor industry is not moving forward.

I also had the Xeneon Corsair 27 inch 1440p 240hz WOLED, it was such a shocking experience that I returned it in 1 week, the screen had such strong anti-reflective treatment that 1440p looked like 1080p++, a colorimetry so bad that I never managed to calibrate it correctly (always a greenish tint and ultra flat colors), absolutely not bright even with the V.105 update (anyway they actually deleted this update, without us knowing why lmao) and the motion clarity was like...wtf? yeah not what i expected, it looked like my Acer 240hz IPS that I currently have ( XV272UX, not available anymore )

Also, Astigmatism and Myopia ( i have both ) seem much more affected by this phenomenon of headaches and eye pain caused by the screen.

In any case, I'm done with the Zowie TN bullshit with their completely rotten overrated strobing which doesn't improve comfort and visibility in motion but actually adds lots of other problems that no one will tell you for various reasons, I I'm also done with its first overpriced OLEDs which are absolutely not sharp and destroy the overall experience and I'm done with the current ultra bad LCDs with their ultra grainy panels from BOE etc.

I finally kept my XV272UX and tested screens in 2022 for nothing! (I must have tested around 15) 4K/1440p and 1080p, what I know is that even if I am presented with a 540hz without "blur" like the Asus which was released, I don't care, the 1080p for me is dead, 1440p...it's not yet comfortable enough for me but "it's okay" and 4K is what I want at all costs, in 2024 I will certainly test some 1440p and a lot of 4K and I would probably go for the QD-OLEDs if they don't have any problems, especially since they announced Glossy!

If I can have a Glossy, I can reduce my headaches!

[Boomchakadah]

That Koorui 27E3QK (rebranded HKC VG273QK) doesn't use PWM dimming. https://youtu.be/z0QcQMDUtNM?t=210. Unfortunately, there are a lot of factors besides PWM flicker that can cause eye strain/headaches, and it's impossible to keep track of all of them. You basically have to try a lot of monitors until you find one that doesn't give you eye strain.

[r0ach]

That Koorui 27E3QK (rebranded HKC VG273QK) doesn't use PWM dimming. https://youtu.be/z0QcQMDUtNM?t=210. Unfortunately, there are a lot of factors besides PWM flicker that can cause eye strain/headaches, and it's impossible to keep track of all of them. You basically have to try a lot of monitors until you find one that doesn't give you eye strain.

The situation is actually not so simple. I discovered for instance that the XG27AQMR doesn't use PWM normally but if you turn on HDR it has PWM below 225cdm2. The Koorui 27EQK ships with a setting "HDR: AUTO/OFF" set to auto by default. Mouse movement is normal with it on the factory auto setting, but when I changed it to off you get instant bad/clown cursor so I always left it on auto.

It's possible the Koorui really did have some type of PWM due to this if the Asus has similar behavior (even though HDR is off in Windows). Either way, the monitor was not usable for me on either setting. It didn't cause a stinging sensation in the eyes after 15 minutes like a 200hz PWM laptop, but it was something far weirder. It made you open your eyes basically to max like some weird eye dilation thing going on and wasn't a problem till you used the monitor for an hour+. Then it just started causing eye discomfort and sort of a disorientation effect.

I don't have the monitor anymore but I'm leaning towards the idea that this particular setting was not actually the cause of the problem on the Koorui because I've had similar eye discomfort problems on other new AU panels. If a monitor has some kind of weird eye dilation effects or stinging eye sensation, both of those are usually caused by backlight fluctuation either seen in textbook PWM or just a high flicker rate, spikey backlight that claims to have no PWM but gives you the same result anyway. This is why I'm having a hard time believing these issues are caused by either QD or KSF when the symptoms are flicker rate related.

There are tools to generate a quantifiable flicker rate % for a monitor. The fact big monitor review sites do not tell you this number when they easily could is suspicious.

[Chief Blur Buster]

There are tools to generate a quantifiable flicker rate % for a monitor. The fact big monitor review sites do not tell you this number when they easily could is suspicious.

While it may be tempting to go the conspiracy theory route because of reviewers given free samples by manufacturers and whatnot, and be encouraged to hand wave PWM away (yadda yadda)...

...It's so obviously not suspicious because of the giant size of the PWM rabbit hole, so I'd call out your use of the word "suspicious". Some of the reviewers already do try to measure for flicker frequencies, but not all do. And sometimes the information is limitedd.

My experience with reviewers is that they are either:
(A) Too small/indie to create a large test suite; and/or
(B) PWM eyestrained audience is too small (<1% to 10%); and/or
(C) Complexity of communicating the information.

Let's not forget household lighting -- even mere incandescent light bulbs.



Frequency is not everything -- you have datapoints like;
- Depth of flicker
- Count of flickers per refresh cycle
- Shape of flicker curve

Some OLEDs, for example, flickerdepths less than an incandescent light bulb.

We have all of this:
- People who get eyestrain from ALL kinds of PWM (even household lighting) -- most population usually don't for PWM above flicker fusion threshold.
- People who don't get eyestrain from most PWM but only specific kinds (weird outliers)
- People who only get eyestrain from squarewave PWM (but not softened PWM, e.g. square wave capacitor filtered)
- People who don't get eyestrain from strobe backlights (1 PWM per Hz) but lots of eyestrain from multi-PWM-per-Hz (eyestrain from duplicate image effects that feel like a serrated knife)
- People who get mysterious eyestrain that was thought PWM but was caused (or more than 50% caused) by other factors than PWM;

Because the display-eyestrain rabbit hole is so big and so full of bad advice, many display reviewers don't bother covering it because everyone eyestrains very differently.

While PWM is a large double-digit percentage slice of a display-ergonomics pie, no single display-ergonomic issue has a majority (not even PWM -- it affects well under 50%). So I have to remind people about Overemphasis on PWM. Now, if we cover PWM, we have to cover tons of other display ergonomics issue. Even websites that refuse samples from manufacturers and fully complain, just are even also ill-equipped to be able to properly fully cover PWM. The "Everything is caused by PWM" elsewhere is rewritten as "One of the major possible causes of display eyestrain is PWM" around here, which is a lot more honest.

You've seen me complain loudly about reviewers and manufacturers, but manufacturing suspicion where NONE EXIST simply due to the ratio of "number of users benefitted":"rabbit hole size and work required" is sometimes too small to be worth it.

The "Major Test Effort":"Users Clearly Obviously Benefited" ratio is a major reason:
For example, proper dead pixel reliability % testing requires a reviewer to purchase 100 samples to see how often dead pixels occur. But reviewers can't afford to buy 100 samples, and manufacturers never ship 100 samples to a reviewer, for large-statistical-sampling-of-one-model attributes. Now, when it comes to flicker testing, you can easily test for PWM, but the problem is there are people bothered by 864Hz PWM but not bothered by 240Hz PWM, and other people bothered by one unit of 1000Hz PWM but not a different unit of 1000hz PWM. So, it's sometimes extremely hard to determine exactly what part of the PWM bothers people (duty cycle, flicker depth, conjunction with other display ergonomic problems, motion-related PWM such as stroboscopics artifacts versus direct-view-related PWM such as flicker fusion, etc). The size of rabbit hole then suddenly becomes bigger than a frequency number, which produces a false narrative, and reviewers don't want to go down the reputation-tarnish path with their end users -- because of the giant wild goose chase / red herring factor.

So, it's not suspicious, that's just a strawman shift-blame word, and I am calling you out on your use of the word "suspcious", r0ach -- it just sounds conspiracy tinfoilhattery when the reasons are so Homer Simpson duh obvious that it's not suspcious.

PWM is a major problem, for sure. The problem is that it's hard to diagnose what definitely is painful PWM.

It's just a giant overwhelming rabbit hole that they should cover if they are able to. But it's quite obvious that the size of the rabbit hole is just so gigantic, given that only a minority of users are affected by even the biggest ergonomic-issue lineitems.

Recommendation To Display Reviewers:

I recommend is that display reviewers just publish a photodiode oscilloscope graph for various brightness levels at common settings (and also provide reference comparisions like average lightbulbs / led / fluorescent) and let people decide for themselves. Numbers should be superimposed on the graphs for the dominant frequency in the flicker graph, but let the flickergraph "tell the story" to the end user.

And, provide multiple flickergraph images for common settings (e.g. 25%, 50%, 75%, 100% brightness settings, HDR on/off, and other common settings), with comparision graphs of other light sources (historical CCFL screen, historical early LED screen, incandescent bulb, average fluorescent, and some random top-rated LED bulb like these tested by some indie youtuber that flickers less than incandescent but still has a minor flickerdepth, etc)

(While not common, occasionally display reviewers do randomly pick up ideas from Blur Busters Forums too. Over 500 content creators use a random Blur Busters testing invention or suggestion)