did you try nicehash miner ? it doesnt require any setting.
I used the nicehash miner with Win 8.1 and Crimson 16.9.2. The AMD R9 390 is just 10S/s. The memory usage is just 25%.
You cannot use all of your memory because all of the zec miners are under test and not stable yet.
I use the nicehash miner with Win10 x64 and Crimson 16.9.2. Amd R9 390X 18.2 Sols/