I haven't checked but even if it is by a small margin, is still not worth it unless you convert to ETH as soon as you mine anything, because growing potential is not really there. Also, 2x 390 you'll have about 500+ power consumption, but you can lower voltage untill it is not stable anymore.
At the current rate of rise of the difficulty, the Etheruem mining with the R9 390 will soon be unprofitable.