i am not expert on linux systems so i decide the keep going with windows, for the MOBO i didnt update the bios rom, instead i have disable the unneccasry features like wifi, bt, onboard vga, and i have set the pci-e ver. 3.0 to 1.0. 
if you try miningOS (is free), there is thread on this forum you dont' need to do anything just flash os to ssd, it have web interface (then you can check system status everywhere), no linux knowledge required. 8 gpu it is better than 7 just try it
i will check it later on, thank you
Dude, you can go ahead with windows 10. I'm running 8 GPU on Z170A Gaming M7. 7 PCIe slots and 1 M.2 Slot.
No freezing no nothing. Only weird thing is, that the MOBO will stuck on every restart (Debugcode 96) so you need to hit the reset button several times
till it jumps from 96 to A2 which will boot your OS.
Im working on a remote solution which will be done over hardware. Because software resets dont work if windows freezes. And also if the MOBO stucks at restart
you cant do anything like Wake on Lan so i have a tailor made solution.
Anybody who is interested: I have a solution to bridge the Jumpers physically on the Mainboard for Start/reset remotely over wifi. (start your mainboard from anywhere in the world)
Costs will be 20 for the module which needs to be hacked (cut away some things and solder some liines)
I will do it for you and send to your desired address guys. (20 already ready to go)
Best wishes