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.
I think it is easier to manage overclocking and watchdogs when you have only one video driver in OS. Both systems recommend to disable onboard video. I've read reports that people run AMD along with Nvidia in Ethos but with issues. And good mining OS must be rock stable.
I see. In my personal experience on Win 10 1709 version. With AMD blockchain, Nvidia and intel onboard drivers I only faced issues with overclocking using claymore config bat. I had random crashes, thread stuck in driver BSOD even when I knew the card runs without memory errors. I switched back to OverdriveNTool and haven't faced BSODs like crazy when using claymore oc.
I was using xubuntu without issues. However, hashrates were lower 0.3-0.5 per card on linux compared to windows and on Cryptonight the hashrate difference was over 100 H/s per card (using two threads didn't show any improvement in linux while it did in windows).