I have a 280X doing 1.15 right now. That's just not mathematically possible over the long run. Luck.
What server are you on ? I've just switched up my settings and in still only getting 1.5 shares per min between two R9 290s
Vanilla middlecoin ATM, but I get high rejects (still the payout is better than the other ones with lower rejects). My rigs don't like useast at all today, but that was my main server. Eu and amsterdam offer good WU and low rejects but also lower payout still.
1.5/m with 2 R9 290 is what you'd expect for a hashrate of 850KH/s per card (WU is about 0.9 x 850 = 767 and U is 767 WU / 1024 share diff = 0.75 per card so 2 cards = 1.5).
850 is what I get with I18, core at default and RAM at 1350.