Last updated: 08/10/2024 All future testing beyond the results in the table will be done with ThorLabs PDA100A2 photodetector as it will likely pickup even minute levels of PWM type flicker. After the latest Windows 11 update to build 22631.3155, I now see significantly more pixel level flicker on the Legion 7i, T480s, and on the LG 27gp95r-b monitor. Still testing... Update: As recommended by @jordan , using Windows 10 1809 (with a manual OS update, instructions below) has led to improvements. Using intel iGPU for T480s and 7i results in significantly less pixel flickering regardless of screen refresh rate (60Hz, 64Hz, or 240Hz). If using the Nvidia GPU on 7i with latest studio driver on 1809, I still see flickering with the screen is set to 60Hz but less so at 240Hz. Installation for Win 10 1809 for T480s and Lenovo Legion Pro 7i: Win10 Iot Enterprise LTSC 2019 (Build - 17763.107) en_windows_10_iot_enterprise_ltsc_2019_x64_dvd_a1aa819f.iso <[removed by moderation]> You may have to set secure boot to off for successful installation. Manually update with this version after installing with the previous iso. https://www.tenforums.com/windows-10-news/152009-kb4538461-cumulative-update-windows-10-v1809-build-17763-1098-march-10-a.html Microscope Videos (240 fps played back at 30fps): https://www.dropbox.com/scl/fo/47fw3ygxkxaq78ul0j19i/h?rlkey=a2fvkmlujs2m9tkmdw59ujwvl&dl=0 Hello folks. I am in the process of testing panels for pwm using Miniware DS213 oscilloscope and BPW34 photodiode + Opple Light Master 4 and temporal dithering and/or pixel inversion with high speed phone camera (240 fps) and microscope (carson microflip at 100-250x magnification). So far: Device Panel Model # PWM Dithering (or pixel inversion) OS Lenovo Legion 7i Gen 8 (Nvidia RTX 4080, 2560x1600 matte IPS) NE160QDM-NZ3 (BOE) Opple: 0.0141 Flicker Index, 7.61% Modulation at 50% brightness 33425Hz None detected with Miniware Yes (in 60hz mode), Higher frequency dithering less detectable in 240hz mode) More comfortable for me but YMMV Window 11 Home 23H2 Build 22631.2861 Thinkpad T480s (2560x1440 matte IPS, Intel UHD 620) LP140QH2-SPB1 None detected with Miniware, Opple: 0.0171 Flicker Index, 8.97% Modulation, 36342Hz at 52% brightness Yes (also with B140QAN02.3 ) Apparently after re-testing both panels show dithering so the T480s is no magic solution. B140 panel seemed to have less pixel dithering. Windows 10 Pro 22H2 Build 19045.4046 Thinkbook 13s G3 (2560x1600 matte IPS, AMD Ryzen 5600U) N133GCA-GQ1 None detected with Miniware Yes All (windows 10 potato edition linux mint xfce…) Nothing worked including ditherig, etc. 🙁 UPerfect 18 inch 144 hz 2560x1600 IPS portable display N/A None detected with Miniware Yes just less noticeable due to higher refresh rate Windows 11 Home 23H2 Build 22631.2861 (tested using nvidia 4080 laptop gpu via usb-c) Eizo ColorEdge CS2740 N/A ? Yes (both 8 bit and 10 bit modes) windows 10 potato edition (ryzen 5700g iGPU via HDMI, nvidia quadro k4200 via displayport), windows 11 23H2 (tested using nvidia 4080 laptop gpu via usb-c, hdmi) LG 27gp95r-b (not recommended due to panel horizontal line artifacts after less than a year of use) N/A Opple: 0.0089 Flicker Index, 4.53% modulation, 34008 Hz (144Hz, 35% brightness) None detected with Miniware (update: yes with thorlabs detector at 20dB gain: https://imgur.com/a/Vc4SVzk ) Yes just less noticeable due to higher refresh windows 11 23H2 (nvidia 4080 via usb-c) The older Thinkpad T480s seems good and never had problems with it. The Eizo also has a rougher matte surface that may be a problem for some. For the uperfect display I could not see dither at 144hz but not sure at 60hz setting. Given the limitations of equipment and threshold at which PWM may still exist, these data are considered measures of relative safeness of the tested devices. For devices with Nvidia GPU, I used their latest studio drivers and also the latest graphics drivers from AMD for the ThinkBook. For the Eizo I was not able to get clear info on whether it was true 10 bit or 8 bit + FRC. These two sites show conflicting info? I should also mention that I also used novideo_srgb and ColorControl but was unable see a difference after setting temporal dithering to disabled. https://www.displaydb.com/monitor/eizo-cs2740 https://www.displayspecifications.com/en/model/21d01e78 I also tested the keyboard backlight of the 7i and T480s. I did not detect any flicker from my T480s. The 7i keyboard light flickers intensely at low enough frequency to be visible in normal digital camera video at 1/8000s shutter speed. To be safer, I would recommend not using keyboard backlighting at all and focus on increasing your natural workspace/living space ambient light levels. The Opple Light Master 4 results seem promising. However, when doing repeated measurements, the reported frequency changes widely from high 30K to low thousands or occasionally even low hundreds for all of the tested panels. However, the results are always reported as "no risk". This is consistent with other's findings about the limitations of the Opple Light Master. 7i Color Rendering Index (CRI) at 96%? Light Master report on 7i laptop internal display measured at 100% brightness on pure white. The CRI is reported to be high at 96%. However the default color temperature of the display is way too blue/high at greater than 8625 Kelvin. https://iot2.opple.com/lightmaster/index.html#/report/01f5aa1814f8481f97d475d204dec4be ~~~~ 7i spectrum measured using HPCS-320 shows Ra of 87.9 and CCK (K) of 6427.

A couple of tips, (1) Isn't it easier to go to the site notebookcheck.net read reviews for laptops? (2) Intel iGPU is responsible for displaying a 2D picture (desktop) in a laptop. Hence the dithering in 1440/60Hz mode. Just disable the Intel iGPU and the problem will go away. (2) Only the IPS matrix does not have pixel flickering? Do not buy laptops with other panels. (3) The problem with the Intel iGPU is not only forced anti-aliasing (pixel flickering), but also de-synchronization ( Input Lag) of image output to the monitor. After turning on FreeSync Premium the problem is solved.

AlanSmith Yes, I know about notebookcheck for many years. It would be easier but I had access to these devices before discovering this site only recently and recognizing symptoms. I have tried HDMI, displayport, usb-c, and from nvidia 4080 and hdmi from ryzen 5700g iGPU to the Eizo and I can still measure dithering even when output is set 8 bit mode to avoid potential 8 bit + FRC feature. I also tested a quadro k4200 running on windows 10 potato edition via displayport and still see dithering. I no longer have the Eizo but I still think it is more likely my gpu/ software combination doing the dithering. For the legion laptop, I have the igpu disabled in bios for testing all external monitors. In NVIDIA control panel, I have tried both 8 bit and 10 bit output. I have tested two T480s both running on intel 620 igpu, same screen specs, same os build versions and drivers, but different panels and differing dithering results. I do this in case it is helpful for others and I do hope more review sites provide more testing beyond just backlight flicker. Based on posts on this forum, it looks like dithering depends on a combination of software (OS, drivers), video card model and the firmware/bios, display, and perhaps even sample variation from manufacturing defect but I not sure about that. For the uperfect, I tested using usb-c at 144hz. If I understand correctly, others are saying dithering is "baked in" to these newer nvidia and amd GPUs now. No idea what AAS matrix is. Still looking…* * https://ledstrain.org/d/2460-ah-ips-ips-ahva-ads-aas-my-experience-with-different-lcd-panels

photon78s For the Eizo I was not able to get clear info on whether it was true 10 bit or 8 bit + FRC. These two sites show conflicting info? An internal source of mine at EIZO claims the CS2740 is true 10-bit. However AFAIK even if it was 8-bit+FRC, in theory feeding it an 8-bit signal would still be okay.

JTL Also I forgot to mention. Same source claims CS2740 is flicker/PWM free.

AlanSmith And notebookcheck.net does not do temporal dithering measurements for all devices. Disabling intel iGPU in bios resulted in no visible change under the microscope. On the Legion, the 240 hz setting can be enabled while the nvidia GPU activity icon shows no activity. As someone still doing and learning 3D web graphics programming, 240hz is only a slight inconvenience for clients but that's another issue for another time. An old arduino demo of dithering (what is the frequency of these algorithms?) https://www.youtube.com/watch?v=1-_JtRl2ks0

photon78s You understand, manufacturers are increasingly lying that the 8bit panels (although in fact they are 6bit + FRC). There should be no dithering on honest 10bit. You can check your monitors/laptops on Android x86 (for your computer). You can install Android 13 X86 (Gapps) on a USB flash drive through Rufus . And run as a LiveCD without installation. Will there be dithering/flickering on 6bit. Or is it a panel problem?

So is the Legion 7i Gen 8 considered comfortable at 240hz then? I'm curious about if the OS could still cause strain even without pwm/dithering

jordan So far so good (a few weeks) using the 240hz internal display and the uperfect montior at 144hz connected using usb-c /nvidia gpu. YMMV. OS/drivers/software/accessibility settings could all matter. So much discussion of that on this forum already. And their is also the panel lottery situation as well. I one point I tried using an usb capture card connected an e-ink android tablet as a DIY alternative to dedicated e-ink monitors for text only work but it was way too slow, bad contrast, etc. Those dedicated e-ink monitors also still have a long way to go but seems to work for some.

photon78s that's great! Maybe I'll consider trying one if my PC I'm building doesn't end up working for me.

jordan FYI, the keyboard backlight flickers on that laptop.

Products to try or avoid? PWM Flicker and Temporal Dithering Testing

jordan

photon78s oh that makes sense then seems like 60hz could be the more problematic thing. That's true about red light I just wonder if IR face/eye sensors is strobing or is emitting a ton of light that makes it not so good sometimes. Thank you! I really hope so too. I'll post how it works for me when I test it.

jordan

photon78s can you post the link to the uperfect you have btw?

photon78s

jordan

https://www.amazon.com/UPERFECT-Portable-2560x1600-FreeSync-Frameless/dp/B0C7Z3ZY3P/ref=sr_1_1_sspa?keywords=uperfect%2B18%2B144hz&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

I returned it as I needed a bigger display. Still currently trying out that lg I linked above. I didn't feel any particular strain during the few weeks I was testing the uperfect. How is the 7i?

jordan

photon78s thanks for the link! I haven't tried the 7i yet. I just got it today but I got a deal on it since it has a bad fan 😅 just waiting for the fan to come in the mail and then I will test and let you know 😄

photon78s

jordan

Beyond the scope of this discussion, I should also mention that I personally avoid monitor EMFs as much as possible although I do not believe I am truly EMF hypersensitive. For example, I prefer monitors that have the AC inverter or switching adapter not built into the main enclosure. The LG has this but the NEC does not. I also measure AC magnetic fields and looking into monitor radio frequency interference. Try sitting as far away as possible is a general rule from both monitor and pc but things get more complex very quickly with nonlinearities. I saw you post on the IEEE standard. This reminds me exactly of what happens in the "EMF safety" field. For example: https://microwavenews.com/

jordan

photon78s what symptoms do you get from emf sensitivity? That is one thing I'm wondering if I'm sensitive to. Btw I did do a EF test on the svd which was high. Is it EMF or EF being the one that causes issues ?

https://imgur.com/a/Wz1EFjt

AlanSmith

jordan Test for EMF hypersensitive

Headaches/burning in the eyes from the phone.
Head burning if GPS-geolocation is turned on.
"Ants run on the head" if the router is turned on.
Headaches/burning in the eyes from a laptop.
Pain slowly increases if the computer is turned on.
Headaches from an alarm/antenna in the car.

photon78s

jordan

By EF do you mean electric fields? Just wondering that perhaps both the EMF issues and the led strain interact together to cause the variety of problem people are reporting. Someone was mentioning taking a calcium channel blocker, which reminds me of this paper which others have "debunked":

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780531/

photon78s

AlanSmith

References and comedy:

https://scottiestech.info/2024/02/07/short-no-more-wifi-debunking-the-debunkers-in-50s/

https://scottiestech.info/2023/10/17/is-wireless-tech-bad-for-you-or-not/

jordan

AlanSmith it's hard to tell if it's from those things or my phone tbh. I'll have to pay attention more and see. Didn't know gps could cause issues. Wonder if Ethernet on a phone could be a lot better.. lol. Not practical but would be good for testing.

jordan

photon78s that's super interesting. I know people in the visual snow initiative community say that k2 mk4 helps VSS as it's a natural calcium channel blocker. For me whenever I use screens my visual snow gets worse.

photon78s

jordan

7i keyboard backlight flicker tested using Miniware DS213 and BPW34 photodiode+resistor. 🙁

https://ibb.co/7VPZ0RZ

Note the frequency indicates 1.00 KHz.

The same measurement system shows flat for the display. Will test 7i again with Opple Light Master next.

photon78s

jordan

I didn't know about visual snow at all. Now I am thinking if the the matte/grainy texture on non-glossy displays would matter at all. I really didn't like the grain/texture on the Eizo for example.

photon78s

jordan

Results are in for lightmaster 4 tests for 7i and LG displays.

photon78s

Video showing screen versus keyboard light (Legion 7i Pro). Taken at 1/8000s shutter speed. Screen is stable. Keyboard is intensely flickering but not visible to naked eye. Do not watch if sensitive.

https://streamable.com/bz0224

jordan

photon78s I didn't watch those videos because I'm sensitive but it sounds like the screen doesn't flicker but the keyboard does? I would be fine with all of the keyboard lights off. I will test it though.

I'm wondering if visual snow is caused by bad screens tbh, mine gets significantly worse after screen use. I also am wondering if a bad matte finish could be a trigger. I do like glossy displays better honestly

photon78s

jordan

You are correct about the keyboard. I forgot to turn it off during my first few days of using the 7i and I think it added to my symptoms.

photon78s

Lightmaster 4 results on 7i main display (2560x1600, IPS, 240Hz).

100% brightness (1.47% modulation depth)

https://ibb.co/B67NmKH

https://ibb.co/FV4RbqP

50% brightness (7.61% modulation depth)

https://ibb.co/r3TqVTF

https://ibb.co/Z8pPvHH

Lightmaster 4 results on LG monitor (lg-27gp95r-b) at 35% brightness, 144Hz, stock contrast (4.53% modulation depth)

https://ibb.co/LCHNLpG

https://ibb.co/KFWw4V0

jordan

photon78s wow looks great. Thanks for that!!

I just wonder if you can pickup any sort of pixel color flickering still with a higher fps camera

photon78s

jordan

Keep in mind that the Opple still has limitations compared to higher end oscilloscopes as used by others on this forum. I have found these screens better for me compared to previous 60hz display and that changing to a high refresh rate mode on these displays changes or perhaps reduces the pixel level flicker and all this without using any software "hacks" or relying on outdated drivers and operating systems.

For video capture of pixel level changes, it would be nice if one had access to those specialized mega-buck high speed cameras. Another alternative is to use sites like these.

https://pixelinversion.com/About.html

http://www.lagom.nl/lcd-test/black.php

http://www.techmind.org/lcd/index.html#inversion

Still hopeful for future tech?

https://blurbusters.com/blur-busters-law-amazing-journey-to-future-1000hz-displays-with-blurfree-sample-and-hold/

"Real life has no frame rate. Frame rates and refresh rate are an artificial digital image-stepping invention of humankind (since the first zoetropes and first movie projectors) that can never perfectly match analog-motion reality. … Also, real life has no flicker, no strobing and no BFI."

"However, the ultimate displays of the distant future will fully eliminate motion blur without strobing. The only way to do that is ultra-high frame rates & refresh rates."

"1000 Hz displays are still expected to arrive this decade"

I do hope the RLCD products can also help with dithering and pixel inversion not just backlight flicker but that remains to be seen.

photon78s

jordan

I actually tried using the 960 fps mode of phone camera for dithering recording. However, the high iso noise becomes more visible to the point might be hard to distinguish between that noise and subtle pixel flickering. I am looking into the Thorlabs setup with high magnification or possibly waiting for mirrorless camera with high iso performance and >240 fps video.

Is the 7i screen at least somewhat usable?

« Previous Page Next Page »