bingo. is 12v powered. any board with a 12v connector powered the cpu with the 12v rail.The pic on MSI's site is really crappy, but I can make out a single voltage stabilizer circuit.
It's very likely that this board powers the CPU on the +5V rail.
EDIT: looking even closer, am I seeing a 4-pin molex connector just north of the northbridge chipset? Is it for the power supply?