Check the JohnnyGuru review, they usually check to see which connectors tie to which rails, then make sure each of the hash boards in on a seperate rail and see if you can tie the controller board connector to the 4'th rail - though at 50 amps a rail you should be able to get away with running the controller from one of teh same rails that one of your hash boards it tied to if the 4'th rail is CPU/Peripheral specific or some such.

 For that kind of money though, I'd spring a little extra for a Seasonic 1200 platinum, or drop down to the Seasonic X-1250 or EVGA 1300 G2 gold units. Did the math a while back, and the extra cost of a platinum PS takes many YEARS to pay off unless your electric is expensive (and in that case you'll probably be losing money on mining anyway).