jordan

Thank you!

I installed 1809 with the update on the T480s (with B140QAN2.3 panel) and it has clearly visible banding. The Lagrom gradient even seems to animate the banding and then stop (minimizing and opening the browser would do that). However, under the microscope measuring the gradient, it is almost completely "stable" and clearly more stable than the 7i on 1809 (might be due to low max backlight brightness causing noise). Perhaps now I am seeing mostly noise + pixel inversion.

https://www.dropbox.com/scl/fi/5h2uk8lz26c7u61zsjtqc/t480s-1809-gradient.mp4?rlkey=dm8cyynb18yfamqo9zw6sg730&dl=0

This is just a 60 Hz panel so this is even more interesting. The gpu is the outdated Intel UHD Graphics 620 not Iris Xe. Also the panel can get significantly brighter than the 7i running 1809 making recording have less camera sensor noise.

For the less flicker sensitive who want to check out videos (T480s 60Hz 1809 best case versus Legion 7i 60Hz Windows 1 23H2 worst case videos of a darker transition part of the lagrom gradient):
https://www.dropbox.com/scl/fo/adv3uvxm0tvi6hndxli2p/h?rlkey=kcsyjrq6p5bf6qprdco9gx4ed&dl=0

Tentatively, the 60Hz T480s running 1809 is similar to the 240Hz 7i running1809 and better than the 7i at 240Hz running 23H2. The worst flickering is with the 7i at 60Hz running the latest 23H2 update.

      photon78s wish I can see those videos but it would throw me off! lol. So your saying that the 1809 t480 is similar to 1809 240hz 7i? Sounds like 1809 is definitely better than that latest win11 on 7i?

        jordan

        Yes, the T480s running 1809 and not win 11 is similar to 1809 240Hz 7i. The T480s has supposedly crap AUO B140QAN02.3 panel I stated earlier, not the LG panel listed in the table which I don't have anymore to swap out and test.

        My good news for the day: On the 7i using 1809 with BIOS set to dynamic and using intel graphics but with no intel driver installed using MS Basic Adapter at 64Hz refresh rate, I am seeing almost none of the typical slow alternating flicker which I thought was pixel inversion. The image under the scope is stable similar to using 1809 at 240 Hz but using discrete gpu. I cannot set screen refresh rate any higher than 64Hz with the basic MS driver. When I go back to 23H2 on the 7i and still using 60Hz panel refresh, I again see the slow alternating pattern of flicker even when I force 8 bit in discrete gpu in nvidia control panel or leave the bios set to dynamic and using iGPU.

        This lead me to believe there is no extra dithering going on the software and gpu side and the output to the panel is 8 bit. With a 8 bit + FRC fake 10 bit panel as you found, this could be another safer alternative. Thanks again for suggesting 1809. Now I have to be careful not to break this setup. 🙂

            photon78s

            wow that's great to hear!!!

            Sorry just to clarify.. so these both are same results no dithering and safe? I seem to do better with higher Hz devices so if your saying 240hz is as safe as 64hz this is awesome!! 🙂

            1. Win 10 1809 ltsc, 7i dynamic GPU 64hz
            2. Win 10 1809 ltsc, 7i Nvidia GPU forced 240hz
              3.

            I'm glad this is working for you. Someone actually suggested 1809 ltsc to me so I'm glad to pass it along! The 7i panel says 10bit on panel look I was only wondering if it's really 8+2frc🤔 if you feel up to it, might be interesting to see results with nvidia set to 10bpc and see if 8 and 10 bit are the same under the micrscope..or if 10 bit dithers. If 10bit turns on dithering than we will know that the screen is 8+2frc and not truly 10bit.

            Edit: not sure how to get the "3." Removed above, won't deleted so just ignore that! Must be a mobile bug lol

                jordan

                For the 7i:

                If you want to use 60Hz screen refresh, use 1809 with intel gpu only. Even under 1809 with latest Nvidia studio driver with 60Hz screen flickers a lot (this might be fixable with modified drivers).

                If you want to use 240Hz screen refresh, 1809 with latest Nvidia studio driver still seems similar to 23H2 with the same Nvidia studio driver (high screen refresh masking my ability to measure dither correctly). So you may not gain much with 1809. I will take a break from this testing lol and try those older Nvidia drivers later.

                Using the 4080, I cannot tell the difference between 10 bit versus 8 bit on 23H2 or 1809. I think the latest Nvidia driver forces some kind of dithering anyway. Update: With 23H2 at 240Hz, it is also difficult to tell the difference between discrete mode or dynamic mode. Later, I would like to see if I could get 240Hz working in 1809 using just Intel iGPU.

                    jordan

                    I accidently left the 7i connected online and it installed the Intel driver. Immediately showed flickering again in 1809. Make sure to test with the Microsoft Basic Display Adapter. Same goes for the T480s.

                        photon78s yikes! I think other than generic driver, old Intel driver and old nvidia driver would be best. If those don't work I think using a quadro turing driver for the 4080 with modified .inf's could be another good option. Not sure how easy it is modifying Intel drivers if it comes down to that

                          I did come across this 10th Gen Intel driver which is for Intel uhd which the 13th gen i9 on 7i also seems to use. Found it on dells website for one of their laptops. It's a 2019 driver maybe it could be a good option if you ever decide to try other drivers. Not sure if it contains other SW so probably look into what the files are before installing if you or anyone trys it.

                          https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=dhc30&oscode=wt64a&productcode=inspiron-15-3593-laptop

                            jordan

                            Do you know of a Windows 10 Pro version that is as safe as the Enterprise version you linked? The 7i and T480s only have Home and Pro licenses respectively.

                                photon78s

                                I can ask around on the telegram group. The different windows builds seem to be a hit or a miss to some.
                                One guy said these were ok with him "21H2 LTSC, 20H2, 2004" while "1909 was the worst one."
                                Microsoft added ACM sometime after 1809 I forgot which build that was and with each build it's tweaked differently so some are okay with certain ones while some aren't. 1507/1511 are the most safe but you would need to modify drivers 100% to make them work with that old of win10. I think ltsc/ltsb is just used for longer security updates.

                                I did find this 1809 DL but unsure if it's the same, maybe that update can be installed to it? https://archive.org/details/win-10-1809-oct-v-2-english-international-x64

                                  Btw if you install Intel drivers make sure to always use "ditherig" to remove dithering from Intel drivers. This could be why it's still a problem I don't think I mentioned that earlier. Just color control for Nvidia I think Is all that I mentioned.
                                  https://kawamoto.no-ip.org/henteko/myapp.html#ditherig

                                  Direct DL:
                                  https://kawamoto.no-ip.org/henteko/myapp/ditherig21.zip

                                  There's also a GitHub post with it's code 😃

                                    jordan

                                    I discovered something interesting with possibly pixel inversion. I re-tested the T480s yesterday night and discovered again some flickering but it looked different than before. The flickering is between linear columns of pixels and the pattern is different but hard to describe. Reinstalled the whole OS and updates with MS basic adapter several times to no avail. This morning and without changing anything in software, I could not discover the flickering anymore. I suspect I may be seeing inversion that has to do with the charge level of the computer (but I didn't charge the computer overnight) or a "cooling off" period/internal monitor temperature/duration the panel has been on. Do you know?

                                        photon78s that's interesting.. I don't know a lot about pixel inversion so I'm not exactly sure unless if room temp can have an affect? Maybe even any USB devices could possibly cause some sort of electrical interference too? 🤔

                                          jordan

                                          Thanks for the link. My question would be if certain low quality panels like probably on the T480s flicker more and more over the course of the day due to poor manufacturing tolerances/design and thus contributing to the computer work fatigue over the work day (you feel fine in the morning and later more and more fatigued as the screen silently increases the flicker to add to that fatigue).

                                          Hopefully in your case you don't have to worry about this. I haven't noticed this yet with the 7i just the T480s. 😅

                                          Not exactly my case but interesting:

                                          Display Power: Why TFT LCD Needs Temperature Compensation

                                          However, cold temperatures cause the switch to turn on slower. This steals time (tΔth) to put through the picture
                                          information, see figure below. Less light comes through the filter glass and the contrast gets lower. Visible results
                                          are flickering and/or image sticking of the display.

                                              photon78s that could be it too. There are known better panels that someone I know uses on dell laptops. Maybe even a panel swap on t480s could be a good option. I hope I don't encounter that with the 7i haha. Not sure which is the most safe with the 60hz Microsoft driver or 240hz studio driver. I really need to start testing the 7i and other devices soon. Just feel stuck in this flare up I'm currently in which sucks!

                                                  dev