does your workstation have more then 12GB ram ?

Try taking one card out and see if it works, ie run with 2 cards and 8GB Ram.
not sure if your using windows, stick in a 8GB USB and readyboost it, or try and match system ram >= with the total ram of the VGA cards.

I know that a guy at work couldn't get microcoin miner to work on his box with 1 R9 290 and 4GB ram.