If you're sure it's the board, just return it.
I tested the UD7 with F8 release at high-volt high-load and found no issue whatsoever regarding stability (http://hwbot.org/forum/showpost.php?p=145651&postcount=100). All I heard of was one guy putting a board to fire, but IIRC the same guy retested with F7 bios and the board went through testing just fine.
Maybe you're just unlucky. It happens.