ASrock H110 Pro BTC+ 13 GPU Board

[Permonik]

Worst mobo ever...

[vladutz1186]

Worst mobo ever...

yeah

[miner29]

Have you tried increasing the boot delay?  I set it to maximum for any motherboard with more than 6 gpu.  Seems to let give the bus time to spin everything up.

[vladutz1186]

I just fix it. I need to set in BIOS to use only one core from CPU, and works fine .. strange !
CPU : G3930

[Atomicc]

I also had an issue with random GPU recognition. Setup was a mixture of different AMD cards 570/580.
When I install all 12 same Sapphire Nitro 570 (CSM disable), works perfect. Every restart pass normal. 

[smc_masters]

Also on my rx580's setups i never plugged the sata pow and got up to 10x cards detected and working..

Make sure when you re plugging your risers to do so in and order per one.
For example first plug the black slot. Boot windows and check everything..
Then start with the white slots one at a time..boot windows check..
If that works proceed like that until all your cards are detected.
Also. For the 13x setup you need 5x nvidia mining only cards and i think will only work with linux based OS.