after doing a little bit of research at the moment i don't think the problem is with your psu or cpu, but much more likely to be either a motherboard limitation or a wrong setting somewhere in bios, like setting pci-e gen to lowest.
personally unless someone else pops in with advice then i think you'd get better help from a forum that's about whatever it is you're mining, than what i'm able to give because i have absolutely no experience with mining and running so many gpu's.
see if this helps.
I honestly have no idea why most people in this sub over-complicate the setup process. Install all your gear like you would a normal PC, no need to plug/unplug/install/uninstall/whatever in some magic order multiple times.
Once everything is hooked up like you want it, just update to the latest BIOS from the EZ Flash menu. Set all your PCIe, PCH, etc to the lowest speed, enable 4G, disable all non-essentials like audio, set graphics to PEG, etc.
Install Windoge 10, making sure to use the latest image. After logging in, your screen will flash a bunch of times as it automatically installs all the necessary and proper drivers. Reboot after doing all your Windoge updates.
Boom, run your miner and profit. That's literally what I've done for all of my rigs, and it works every time, especially with the Asus Z270-A (which I have a couple/few of). I've only had one issue with one board that couldn't be solved by updating the BIOS, and it was because that board didn't automatically enable XMP. Once I enabled it, everything worked flawlessly.
Edited by terry1966, 10 August 2017 - 06:39 PM.