17mh/s sounds like your card isn´t running in compute mode. You need to change this in the AMD Settings.
Global settings -->gaming-->GPU workload-->switch fro gaming to computing.
any possibility to change all the GPU to compute without going to change one by one?
Yepp. Several possibilities: Ethos, Simpleming OS, HIVE OS. I prefer the last cause it can run AMD and NVIDIA along in single system ;-)
You can pretty much run both together in any ubuntu 16.04. I am surprised that Ethos and SMOS doesn't allow mining both together.