flicker

Hi! I'm a bit embarrassed but I'm stuck, not able to get rid of a screen flickering during boot, between the screens of GRUB2 and plymouth. Both GRUB2 and plymouth are OK. It has this sequence: ... GRUB menu > black screen > text ("Booting openSUSE Tumbleweed Slowroll ... loading initial...

Just installed my new monitor, all settings seem fine I'm running 165Hz. From time to time it seems to lose contact/reset/turn dark, but returns. I've observed it at the moment just in Linux using Nvidia driver: 515.65.01. It does not seem to be a system config since I had never suffered with...