Post more info about the system.What version is the motherboard and what BIOS version you use.
I am having the exact board ,version 1.1 ,with a 5600K and i can tell that apart from the LLC settings the board seems ok.
Nice overclocking done easily.
Using the VGA output with an LG LCD LED.
Never had issues using BIOS.
I would say the problem is the display used.
Use BIOS version F5 with 1.0 and 1.1 hardware versions.