Motherboards make a HUGE difference. I only use higher end ones. The little extra is worth all the time and headaches saved.

Powersupply is another big thing.

You are right. The very big dissapointment for me is asrock h110 pro btc+.
I always stick with asus, but for one time I bought asrock. The mobo is not stable and they are not issued new bios since  release...

Thanks Mythic. I'm stumped.

I used this method to get devocon.exe:
]https[Suspicious link removed]

Then followed your instructions. Still get the same error:

I have to disable, then enable each GPU, which still works great. Still a pain though.

Just put this at the begining of your bat file. And it will start as admin...

@echo off

:: BatchGotAdmin
:-------------------------------------
REM  --> Check for permissions
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"

REM --> If error flag set, we do not have admin.
if '%errorlevel%' NEQ '0' (
    echo Requesting administrative privileges...
    goto UACPrompt
) else ( goto gotAdmin )

:UACPrompt
    echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
    set params = %*:"=""
    echo UAC.ShellExecute "cmd.exe", "/c %~s0 %params%", "", "runas", 1 >> "%temp%\getadmin.vbs"

    "%temp%\getadmin.vbs"
    del "%temp%\getadmin.vbs"
    exitB

:gotAdmin
    pushd "%CD%"
    CDD "%~dp0"

Hey, what other coins would you mine with a vega right now ?

Interesting, once again it is the x16 slot which wont run the vega (same issue for h110 btc).

This slot is wired directly to the cpu logic instead of the others going through the southbridge first.
Though the z270 has actually 3 (max) wired directly to the cpu ...

Tried toggling HBCC in global settings, devcon.exe, nothing seems to turn on HBCC. I have 12 GPU rig prepared but this ... HBCC just does not work on 12 GPU drivers.

I went for an ASUS B250 Mining Expert and have a v64 and a v56 @ 64 along with a 1080 ti running stable. My main issue to date has been trying to get power draw at the wall to resemble hellae and everyone else's whilst maintaining high hash rates. I've found that the only way to curb power draw is to set core to go 1308/1100 @ 905 mV on both Vegas, 1408 core increases power draw at the wall by 100w for a ~200 h/s benefit. With the 1080 ti mining Zcoin (135w) total system power draw at the wall is 495w and the Vegas hash at 3650 h/s. That's not as good as I had hoped and I'm beginning to think the motherboard is the culprit. Power supply is rm1000x so I don't suspect that is the issue. Risers are 006c powered via 6 pin PCI-E, could they be causing higher power draw? Have followed all the guides and used hellae and my own custom power play tables - this has me stumped...

I've also seen an asrock h110 unstable when the x16 slot were in use (through x1 riser).
Strange...

i have like 6 peices of the 270 A and AR asus and they work with up to 8 gpu rx 570 or 580 easy

are you sure you dont have a bad board? they really have problems with 6 plus vega?

I hope not becuase i like these boards since they have their own power switch too and have been for the most part solid.  I only have 3 vega so i cant test it myself

did u update bios to latest?