Just built a new rig with an ASUS Z170 Deluxe board. Moved my boot drive from my old Dell T1800 to the new rig. Everything works perfectly except the shutdown/power off. Linux seems to shutdown correctly and the screen turns off but then the CPU fan starts spinning really fast so I assume the CPU is stuck in some loop. No hard disk activity. Have to power off with the power button.

Tried both "shutdown -h 0", "shutdown -P 0" and "shutdown -h -P 0". No difference.

Anyone knows what's wrong?