Using TWO PSUs on the same system is the issue IMO.
I don't think so. It was never an issue with older cards and I have excess power.
no, if you connect it properly...
Trimegistus did you check it with another miner?
Like I said before, the rig won't even boot.
I'm going to purchase some decent powered risers, I'm now convinced it's a power issue derived from the fact that the 480s are sucking a lot of watts from the PCi-e bus.