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I think their are basic principles but no one size fits all solution. It's useful to see both the personal experiences and the "objective" measurement data. What's interesting is when the subjective experience does not seem match the measurements.

FWIW, I'm not a professional programmer but prior to more severe eyestrain and discovering this site I was doing a moderate amount of graphics related programming (VSCode with default white and darker material theme in the evening, windows 11 using both mix of both integrated and discrete gpu modes). I attribute eyestrain to switching from 240hz to 60hz refresh rate on a laptop screen and increased "stress". I do not remember ever having significant eyes issue during the windows 7,8,10 and using laptops with wide gamut support and/or PWM like the thinkpad w520, t500, etc. which I not longer have for testing.

GregAtkinson

How do you define "reasonably low flicker" in your oscilloscope measurements? I have been using 20dB gain on the detector but have tried higher gain settings but that makes it even harder to find a device with a "flat" waveform.

      photon78s How do you define "reasonably low flicker" in your oscilloscope measurements? I have been using 20dB gain on the detector but have tried higher gain settings but that makes it even harder to find a device with a "flat" waveform.

      Before I answer that, let me refer to this chart. I pulled these numbers from the Thorlabs site:
      10dB = 3.3x
      20dB = 10x
      30dB = 33x
      40dB = 100x

      Here's my favorite (now dead...) laptop. Barely any flicker at 40dB/100x magnification:

      Here's the same model, but with a different panel. This is unusable for me. I assume the flicker is what makes it unusable, but I can't say that for 100% certainty - maybe something else that can't be picked up by the photodetector (like FRC or pixel inversion) is causing the problem.

      Here's the LG 27MQ450-B at 100x magnification:

      I have the waveforms for all the monitors in the table a few posts above in case you want me to post a few of the waveforms. I'm too lazy to post all 20 of them though. :-)

      If you want more details, you might be interested in this thread:
      https://ledstrain.org/d/2598-help-wanted-to-measure-flicker-andor-test-a-flicker-free-monitor

          GregAtkinson

          Thanks! Similarily, I can tolerate this (lenovo legion 7i 2023 at max brightness measured with the thorlabs detector but using only the Miniware DS213):

          But not this (samsung s10+ at max brightness). Both at 20dB.

          The lenovo screen at max brightness, detector at 40dB, and oscilloscope window at 10mS.

            3 months later

            Sunspark I am wondering, does it apply to laptops and integrated graphics?

            For instance, if after Windows 11 installation, all other non-problematic os became bad, will it help to unplug the CMOS battery for an hour?

              a month later

              I finally figured out why the position of my main monitor on my dual monitor stand determines whether or not I will have a dizzy feeling at my desktop. It's because when I have my main monitor on the left, and I'm positioned more to the left of my desk and facing straight - now positioned closer to and facing a room corner - there is less air flow and my exhalation doesn't circulate out as well, leading to higher CO2 concentration levels. With the main monitor to my right, I'm sitting slightly more to the right and facing diagonally to the open part of the room where there is better air flow. The better air flow in the center of the room is in part due to how air works in a room but also due to the channel of air circulation I create with my tower fan that moves air coming in from one vent then out the door on the other side of the room.

              This dizzy feeling is the same feeling I get when I've either kept my doors closed for too long or had inadequate fan circulation channels (Where air may be moving a lot due to different fan sources but chaotically, making it hard for air to efficiently enter one side of a room and exit the other. This can be caused by air purifiers or poor fan setup).

              It's always been CO2. So what I can do now is either move my monitor to the right position of my dual monitor stand, which I've done, or move my desk which is hard to do with my current room layout. I recommend people experiencing dizziness to consider air circulation in the position they use their computer.

                You guys can write such a long text, what a patience.

                TrantaLocked I keep as far as I can. I even recommend getting 2x of the same desk, so you could place monitor far away and increase scaling. Also, disable all sensors, install ditherig.exe and pick explicitly sRGB color profile on monitor. Also set wifi transmit power to lowest. All these remove all dizziness. Also, do not use windows 10, use windows 11.

                    Donux Yeah maybe. I'm still trying to figure that out. I was using my Samsung 2494 CCFL LCD for about a year with no eye strain and then it randomly developed a green hue and color banding a few days ago and I decided to put my Acer VA LED back to the right position. But even then I still feel like I've been having more issues after my last post. Could EMFs actually be involved? What kind of EMFs can monitors produce?

                    Anyway, I opened up my Samsung 2494 monitor, blew on the video processing PCB and reseated the internal display cable on both ends, and miraculously the green hue and color banding are completely fixed. First time I have ever been successful in a monitor repair or modification attempt.

                    I am very happy about this repair success because I have used this type of Samsung CCFL LCD for my main monitor for over a decade and really do not want to switch until I can buy an affordable OLED/MicroLED monitor where there is no chance of backlight color temperature being a problem. I have given up on all of the modern LCD panels because it always seems like something is wrong. My Samsung is just nicer to look at. It has the typical greenish backlight temperature and a coarse grey colored matte coating. Despite being tech from 2008 and having PWM, it's really good.

                    I do still think I'm having circulation issues in that side of the room regardless of the monitor. I will probably need to buy a second fan and place it in the corner facing the direction the existing air current goes.

                    There are some OLED monitors now at the size I would want. Any of them actually good? With them now reaching around $500 open box, $100-200 OLED monitors may not be that far off in the future.

                      5 months later

                      Has anyone tried Xaomi 4k 27 inch monitor ? This is as I understand direct from Chinese brand, which is the only one that is marketed not just flicker free which means nothing, but they write DC dimming (hopefully not partial).

                        Donux Has anyone tried Xaomi 4k 27 inch monitor ?

                        There has been possible concern raised about recent Xiaomi monitors on this forum

                          Donux Xaomi 4k 27 inch monitor

                          Xiaomi mi 27 2k 165hz with AUO panel was bad, sold

                              simplex I have inspected their website and to be fair they did not mention any where that this is flicker free, or if its DC dimming. Only mention is TUV low blue light. So if they do mention this on other products, and do not mention on this one, then clearly it is not flicker free.

                              I hope someone could provide feedback on Xaomi 4k 27 model where they claim it is flicker free TUV certified and it is DC dimming.

                                  Donux I think the consensus here is that TUV flicker free certification is questionable at best considering a) the specifications aren't open and b) they were involved in the Intel "eye strain investigation" which ultimately didn't identify or resolve the root cause of certain issues.

                                      Donux this is flicker free, or if its DC dimming

                                      My monitor was DC dimming, but FRC had artifacts ( vertical columns ) which flicker left-right each new frame

                                      Also, TUV low blue light hardware solution seems better option: in this case blue spectrum peak shift from 445..450 nm to 460..465 nm (new LED chip type used) or new coating used ( filter/reduce blue light intensity )

                                          JTL It is still important to assess the product end to end, i.e. from actual communication by the brand to the actual symthoms. Regarding flicker free I was more considering that in combination with DC dimming, which seams to be specifically written for this Xaomi brand, others do not get that into technical details. But I am researching this too, by simply writing email directly to the company to get answers.

                                            simplex Yes true, native bit probably also should be researched on this. But I like to research step by step in order to assess this specific product. But also, even if there is a lot of misinformation, sometimes consumers themselves doing a bad job in reading the specifications. I want to believe with some homework, maybe few emails to support of the company, it would be than stop this all over the place trial and error and have rigorous questions to ask, in order to determine if product is right for you. Once we have this, we are all set. Simply extract this data from the company, and off you go, buy the product. This way you will derisk your purchase as much as possible.

                                                Donux

                                                I personaly got gw2790e with LG panel and it seems good at 60hz (6000k basic temp, no flickering)

                                                Someone in reddit told gw2790q is also good

                                                  Select one among these three monitors: Viewsonic Samsung Philips

                                                  (Fast-IPS is best, there is no one willing to produce VA monitors now, and TN is just white-ish.)

                                                  dev