Well, tried swapping the powersupplies as I've had some trouble powering up this computer as well (occasionally, it just doesn't want to.. You have to fiddle with the main power switch a couple of times to make it turn on).. And the indicator immediately went down to 3.302V.
Edit: TO my knowledge you can't regulate this voltage thing at all.. I certainly can't find a way. It seems all motherboard/psu controlled.. And like I said, changing powersupplies made the overvolage thing go away. The PSU swapped with was the same type of supply. Aopen FSP300-60BT