Are you 100% sure it is drawing 950Watts for 2.9MH?
This sounds TOO good to be true
I belive the 270's "non-x" are great value right now, u can squeeze almost 500kh/s (475-490) from them for ½ price (210$ in Sweden with BF4) of the 280x (385$).
My kill a watt-adapter measure's values from 940-980W @ wall on 100% load. I downclocked the CPU and no connected fans.