30sec or 2min black screen after restart or shutdown, windows 7 dont have this problem. problem is AMD display driver, delete display driver and restart/shutdown super fast. im instal all versions and try all vbios, fast start in windows is off.
z390 taichi ultimate mb (try all version of bios), radeon vii gpu. i reinstal windows 10 17 times! but, im try windows 7 with drivers from this site and latest video driver from amd site, and all ok, all super fast.