Upgraded to the Seasonic X-650 Gold 750W, and day power consumption reduced to 870W. All at 350MHz.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151087
850 W sounds like a lot for 3 hashing modules @ 350 MHz. This is at 120 V?
I am at 230 V and my default Batch #2 units with the 850 W power supply (enermax) pulls 765 W and the units I converted to a SilverStone Technology Strider Gold ST1200-G run at 735 W (92% power factor)
To be honest I am thinking of upgrading from corsair AX860i to AX1200i so I can test oc settings in the 375+
The AX860i is rather impressive and puts out little heat.