Windows 10 Version 2004
Solution for me is rebooting in "Windows 10 Audit Mode" ;
typing : "%windir%\system32\sysprep\sysprep.exe /audit /reboot" after running CMD (command prompt) in Win10 reboots the computer to Audit mode and it changes (on my PC) the rendering (or how Windows functions with the display driver) in a way to substantially reduce (or nearly eliminate) the eyestrain/headache/mental fog symptoms I've been experiencing with my i5-6500 PC since late summer.
I've been using Windows 7 in VGA Basic adapter mode (Intel HD4000 disabled; enabling the driver would always cause headaches) at native resolution on an older Haswell based laptop and a separate pre-Haswell (2012-13) desktop running Intel graphics (driver enabled) through the VGA output (not DVI or Displayport) and it was also good with Win7. Both configurations were very comfortable at 100% hardware brightness to suppress PWM, but
I needed a higher-performance computer running a more current version of Windows.
I had purchased an i5-6500 based desktop running Windows 10 in late summer (preinstalled with version 1811 I believe, but later upgraded to 2004, 20H2 and then 21H1) but I had been grappling with eyestrain, reduced mental focus and ringing in the ears whenever I used this "newer" PC with all of these Win10 configurations. I've tried three different 4K monitors (LG 27UK500, Benq EW3270U, Lenovo L28U-30) along with my 10+year old TN FHD monitor (which was fine with the older PC running through VGA/analog output) with this newer PC (running Displayport via the integrated 530 graphics, or HDMI through a separate Nvidia 710 graphics card I purchased to see if it would help) and I would still get the same symptoms. Some days were better than others but it was never nearly as comfortable to look at and use as my 2013-2014 PC and laptop. The symptoms were slightly worse when I was running through Integrated Intel 530 graphics enabled, but they were still noticeable with the Intel driver disabled (ie running through Microsoft Basic Display adapter mode). The Nvidia graphics card didn't make any real difference, either.
I even tried installing Windows 8.1 and Windows 7 on this i5-6500 PC and I used it with Intel 530 drivers enabled or disabled (ie Basic Display adapter mode), and it was never fully comfortable. I was disappointed that even "trusty" old Win7, which had been very comfortable on my older 2012-14 laptop and desktop, was still providing symptoms with this i5-6500 PC, regardless of which monitor I connected it to. I also ran the monitors at 100% brightness to eliminate PWM. On the side, I don't believe most of the newer monitors advertised as "Flicker-free" have true unchanging illumination intensity at sub-100% brightness; from my own experience, I would always experience additional eyestrain or headaches at brightness levels under 90-100% settings, even on monitors advertised as Flickerfree or using DC modulation to control the backlight. And I'm certain it's not placebo.
Anyway, to make a long story short, I've been reading the ledstrain.org threads over the past several months and the consensus was that only the earlier W10 versions like 1511 would be comfortable for visually-sensitive individuals but I was never able to get a copy of this.
Somehow I read about rebooting Windows 10 in Audit mode and I tried it and to my great surprise and relief, it felt immediately more comfortable....and this is with the Intel HD 530 graphics driver ENABLED.
To my great surprise, running this system on Windows 10 21H1 in Audit mode with the Intel 530 Graphics enabled is much more visually comfortable (and provides better mental endurance and clarity) than running the exact same hardware (4K monitor Displayport native resolution) with either Intel 530 graphics driver enabled or disabled (Basic Video Adapter/VGAadapter mode) on Windows 10, 8.1, or Windows 7 at the same 2160p resolution.
I can't explain logically why this works since I'd assumed that Windows 7 or 8.1 running through the Basic/VGA adapter would cause the least additional image processing, but apparently not in my case. Apparently the Win10 Audit mode, at least on this i5-6500 setup, gives the cleanest most comfortable image.
Anyway I just wanted to share this with the group and perhaps running in Win10 Audit mode will provide much needed relief to some other people as well.
jthompson7804 Are you still using Audit mode?
Until December I could use my private PC (Win 10 Pro, 21H1) with a VGA->DVI cable without eye strain. Since December this no longer works (although nothing was changed at that time, but I had a lot of stress).
My work laptop (win 10 education, 21H1) is still somewhat comfortable (at least significantly better than the private pc). I have yet to find out if this is due to the Intel GPU/drivers, the special enterprise image, or Win 10 Education. When I boot Linux (on a USB stick) on the work laptop, I have eye strain again.
Yesterday I completed the assembly of the new PC. I decided to keep the monitor and GPU and change everything else. I switched from a ryzen 1700 to a 7900X.
I installed W11 with updated drivers and after two hours of use I was very sick. Disorientation, headache, etc., the same thing had happened to me with the old PC and W10 2004.
I have an ISO of the old SSD so I will try to restore the image and go back to W10 21H1 and hopefully be able to use the PC.
I am really sad 
mmm i am not sure to be able to go back with W10 21H1… the ryzen 7000 is not official support! Let's hope it works anyway...
Small update:
I was able to clone the old SSD so now I have the exact same software as the old PC, same GPU, same hdmi cable, and same monitor.
After an hour I am in terrible condition so something is not working.
The NZXT X73 liquid cooling pump is making a noise that is driving me crazy, tomorrow I get the corsair H150i! I would like to hope that the problem was related to that noise but I doubt it....
The alternative is that the motherboard is doing something different in the PCI-E slot! But it's a gen 4 like my old motherboard....
I feel like I threw away 2000 euro, so sad!
Is the gpu driver the same as before ?
You have the same os version as before right ? I suspect then it's indeed the motherboard. Not necessarily the mobo is "bad" but probably you have to find the right os version that is "compatible" with your new mobo. I have a hunch windows 10 versions are not necessarily good or bad per se but could be good or bad according to what mobo you have.
Personally, on my current laptop, windows 10 2004 is very bad but 20h2 is better and older versions are also better. I suggest you try older versions.
Lauda89 Hi there,
Just to clarify - you’re running the same software, same GPU, same cable and monitor and only a different processor & motherboard.
In my mind there’s only three things that could be up here:
- your HDMI is plugged into the motherboard HDMI and not the dGPU, meaning you’re using the Ryzen GPU. I’m guessing this is not the case but worth mentioning. To be sure, disable onboard graphics for your motherboard in the BIOS.
- Your GPU drivers have updated in the change. If it’s an Nvidia GPU, open control centre and make sure your resolution / bit depth / full or limited range colours settings are the same as previously.
- Don’t take this the wrong way, but I often experience a) a lag in my symptoms - they take days to ‘reset’ b) a negative version of the placebo effect when I change something and c) an exacerbation of symptoms due to stress. It could be worth trying to stay away from the machine for a few days and let your brain reset before trying again.
I know how frustrating this is!
But really it sounds like if you have the same crucial hardware and same software, there’s not really any way there can be a change in symptoms, which is actually a positive thing.
Fingers crossed for you.
Yes all is the same, GPU driver and OS.
Of course when I booted the PC, windows noticed that the MB and CPU are different so some driver updated it (like PCI).
With the old PC I started having problems with 1909 and 2004, then 21H1 was fine.
I honestly thought I could be safe by keeping the same GPU, monitor and software but apparently something is not working as it should.
With the microscope and 240FPS recording I see no difference in pixels between the two PCs.
si_edgey
Yes, different processor, motherboard, RAM (DDR5), PSU and case.
No i am using the HDMI port of the dedicated GPU. Obvious that in the device manager I see two GPUs right now but the integrated one has "windows basic" as drivers. I might try disabling it (the integrated one) from the bios and see if it changes anything but I doubt it....
No, the GPU driver is the same (AMD 21.10.02) but windows told me that something related to the pci interface was updated and a restart was needed. So something happen..
I absolutely agree. These days I am still sick from the first attempt so I will have to rest a week and then make a second attempt.
If I don't find the solution with software I will have to try an nvidia GPU. I don't see it as a problem because by now my RX 480 is old and should be changed but there is the usual problem--I can't know if I will be able to use that GPU.
I will keep you updated.
Thanks for the help 
- Edited
Lauda89 windows told me that something related to the pci interface was updated and a restart was needed. So something happen..
I would retry the cloning and use it offline and use an update blocker
If it doesnt work, try Win 11 without activating it. Perhaps it is some driver problem.
Try 20H2, it's been the best for me.
Liberator005 what are your specs of the PC?
jordan Right now, a lenovo legion 15 ICH laptop. CPU : i5 8300hq. iGPU : intel uhd 630. dGPU : nvidia gtx 1050.
On My Zephyrus G15 I can't find any os safe for eyes.
What's for you the best between:
21H2 LTSC
20H2
2004 ?
Thx a lot