GA-970A-DS3P - cannot run more then 3 gpu's - PLEASE HELP

Hi, I bought gigabyte GA-970A-DS3P for which I know MANY miners use, it should run 5 gpu's without problem. When we run 1 gpu up to 3 gpu's it works, when we run 4 gpu's imediatelly after hashing stats pc just powers off, it is not PSU issue since with same setup, same cards, same everything other botherboard works, we also tried all bios versions for this board. We double tested all HW and same setup on 2 diff boards, all fine, on this one, simply when hashing starts with 4 gpu's->power off in 2-3 seconds.

ANY idea?

THANK YOU TONS!