the issue here https://www.youtube.com/watch?v=0KDi9EDnYmg it is triggered when i manually shut down and power on again the monitor. and only when the amd drivers are loaded (everything is fine in the bios and when i uninstall the drivers) i can solve it rebooting the pc. trying a different hdmi cable or disconnecting it wont solve it but changing hdmi port on the gpu solves the issue until i poweroff the monitor again. then both hdmi ports will have the issue until reboot. it blinks green if i change monitor Hz, and goes back to black if i revert to 75Hz. disabling freesync won't change a thing)
until i do not power off the monitor everything is perfect. i can run demanding games on 1080p high/ultra settings for hours without problems.
another thing, maybe important: the hardware troubleshooter gives me the error 0x8000FFFF only when amd drivers are installed. i tried 4 different version of the drivers and it is always the same (one older, 2 new beta and the actual stable one).
also no problems after waking from monitor power saving mode.
what other tests can i do? i only have this machine and another one with an old vga monitor and a r7 260x