with 270 ~265

270 is exactly the same as 270X, just binned lower - so I guess smolen was right.
Weird that I'm still so much faster on 270..

310MH/s at 1123MHz.
280x is about same speed as you or smolen, 510MH/s at 1150MH/s.
My miner is full sgminer with all algos working, works fine with multi-algo in nicehash.