Holy shit, how did that happen? Did you overload the board with multiple high end GPUs? You need one of those ribbon extenders with the power molex man. That'll offload current draw directly through the PSU instead of through the motherboard.
so 3 single GPU cards is too much?
It's a bad design........ don't put 6 PCI-E lanes on a motherboard if It can only handle 2 cards.....