I have a new GA-Z270X-UD5 motherboard and when I make changes to the bios settings the computer will reboot for about 2 seconds and reboot again in a cycle several times. After about 7-8 tries, it will turn off and start the reboot cycle again. Eventually it will post and I will be able to press F9 to go into the bios settings. There will be a message to the effect that the bios settings are reset to default settings. I've flashed the bios to both version F2b and F2 and it didn't clear up the problem. I haven't had a problem like this with my previous Gigabyte GA-EX58-UD4P motherboard. There was a time when this would happen under the F2b BIOS that the motherboard reverted on it's own back to the version F1 BIOS and would default my boot drives to my external SATA drives first. That problem has been cleared up I think when I upgraded to the version F2 BIOS.