I've scanned this thread and hopefully I can add some perspective as I own multiple 970 cards and have owned more in the search for a good config. I've also been through the whole good setup gone bad multiple times over the years.
Once upon a time I had Windows 10 1909 running super sweetly with a Gigabyte G1 Gaming 970 card with no eye strain at all (z97 mobo and 4790K cpu). It was great. But then my motherboard blew up - I think taken out by my SSD, which died at the same time.
So, I bought a new motherboard, CPU (10700K) and SSD. Nothing I did would get me a working setup. They all produced eye strain, even using Win 10 1909 and the same video card, hard drives, cables, screen etc. And certainly none of the newer builds of Windows worked. I knew of discussion here about using older WIn 10 builds and none of them worked either. Conclusion - the motherboard was doing something nefarious. On top of this I suspect Microsoft had added something new to the 1909 build.
(Intererstingly, my son is now using that CPU & motherboard with another G1 Gamng 970 card and it's runs the latest Win 10 build without too much eye-strain. But I guess if it was my main then perhaps I might change my tune).
I tried other 970 cards that I knew were 'good' with this setup and still no joy.
So I replaced the blown up motherboard with something fairly similar (same z97 chipset, albeit a different manufacturer) to resurrect my old 4790K CPU. Win 10 1909 still wouldn't work nor did any of the newer builds available at the time, all causing lots of eye strain… but lo and behold Win 10 1511 worked! No eye strain at all.
Since then I've been happily running this old build, locked down not to update, without too many problems. My advice to you is go back to an older build of Windows 10 like 1511 or maybe 1607 and start from there.
Some additional notes:
- Most Unity based games cause eye strain. Don't use anything like that for testing.
- Some browser versions can also cause eye strain. Thankfully, Edge seems pretty good. Start with that, not Chrome.
- Subsequently, due to positive comments in this forum about certain Win 10 releases, I have tried newer builds of Windows 10 but none that I've tried have provided a good initial experience. (Part of this is that Win 10 1511 can't run a newer .Net version that some apps are now asking for).
- I have had experience of good 970s going 'bad' and I subscribe to the theory that some config that impacts us can be written to the card (by video drivers?), changing its behaviour fundamentally. I have ultimately overcome this by going back to an old Windows build.
- I run DVI (card output) to HDMI to a VGA adaptor to the screen. This doesn't really do much but I figure even if it softens the image anything that softens the digital 'nastiness' could be a good things.
- You can have a good working setup and try a different screen and it's eye strain city.
I know for a fact, having bought and sold multiple of these video cards that they're not all the same. Of the dozen or so G1 Gaming 970 cards I've owned:
- V1.1 hardware always causes me eye strain, and these get on-sold.
- V1.0 hardware is a lottery - Hynix RAM is A-OK, and Samsung RAM is bad (they get sold too).
The VBIOS version doesn't seem to make any difference that I've been able to detect, and these days it's super hard to get specific versions. I'll add to this that I've tried and failed with 980, 980ti, 1070, 1080, 1080ti, 2080ti, Vega 64 graphics cards with every one of them causing eye strain. All were bought and resold, sadly!
Don't give up, just take everything back to basics. And if you get something that works. Make a good backup!