It started when I installed gfx driver above 4664.
But now I cannot install driver 4664, it writes that this driver is not suitable for my PC. Do you know why?
Yes, I have tested hdmi to hdmi connection with my TV (not 4K). And I did not see any flicker.
I guess the most simple and obvious solution is to buy a new monitor. But may be I can do some kind of tuning since flicker disappears when the game is running. Is it possible?
Diminix, thank you for that information.
If you would like to install driver .4664 use this method: Manually Install an Intel® Graphics Driver in Windows® 10 and Windows.... The error message you see could be related to the installation method because this driver should work fine with your Intel® NUC model. The test you have done with the HDMI to HDMI connection, indicates me that the flickering behavior is related to the adapter you are using. If the driver wasn't working it would have shown the same flickering with the HDMI to HDMI connection. So, is there any chance to test a different adapter? Actually, you can find some HDMI to DVI cables that have been officially validated here: Intel® Product Compatibility Tool
I've tried a hdmi to dvi cable. But not a cable which is officially validated since I do not find any of them in my vicinity.
But without success, screen was still flickering.
I removed current driver and installed driver 4664 using the suggested method. After that flicker disappeared, even with my first adaptor.
In some minutes system automatically updated driver to version .4815. And flicker is still disappeared.
I am going to test the system for a couple of days. I hope the issue has gone.