I would love to find out how you have your cards set in the bamT.conf. I am running 1 Sapphire R9 290X Tri X (model 11227-00-40G) and i am only getting 671 KH/s.

Here is my setup
990FXA-UD5
AMD Sempron 145
Seasonic X850
Sapphire R9 290X Tri X (Model 11227-00-40G)
4GB memory
All in a Cooler Master HAF X