ich have a probem with my Sapphire R9 Nano. I connect my Nano with Displayport to my iiyama Red Eagle Display. When I set CSM in Bios to "disable" then i have after a longer boot, when the Monitor goes in standby (for example after changing the clock of the ram) no Signal anymore. I have to restart the PC. This only happens on displayport and only when CSM is set to "disable" which is neccessary for Secure Boot. I use the UEFI Vbios for R9 Nano by AMD.
Thanks for helping!