I learned a valuable lesson today and wanted to share.  I have a 240v PDU which has two 16 amp breakers built into it (6 plugs on each side).  I was installing a server PSU -1200w and using an standard PSU 850w to run the board and the risers.  What my mistake was that smoked 4 cards was plugging the 240v server psu into one side of the PDU at 240v and the atx psu 850w 204v into the other side of the PDU.  Apparently the two grounds (i think) one is A-side of panel and other is B-side.  I had successfully done this with my first rig, but was lucky enough to have both power supplies(Server & ATX)  plugged into one side of my PDU.  I guess this is lesson learned and if I had done the pico like I  was thinking the power would have all come from the server 1200 watt power supply.  Well I am going to try and RMA them, but they smell bad.  I just picked up 2 more sapphire rx 470's and was planing on building a new rig.  Guess I have room for them know.  Sometimes a lesson is learned the hard way and hopefully it just costs me time and some lost hash. :-(   Don't you just hate when you do stupid stuff?  I lost my test rig last week to a power supply that I had unplugged and it still had charge i guess.  When I went to plug it into an old test motherboard with 2 pci-e slots, it discharged and i heard it.  Put a new supply into the board and nothing.  I guess its just not my week!