On the new H97 Anniversary ASRock Boards, if you have 3+ cards it wont boot unless you plug in the molex on the board. At least that was my experience, even with USB PCI-e risers.
I confirm that, I have a H97 Anniversary and mobo doesn't boot if you don't connect the molex on the board. I'm using it with 5 cards.
At the end my mobo is fried.
This morning I checked it because I couldn't connect via SSH ... and...
The problem is like roitpls said, if you don't connect the molex in the H97 Anniversary, the mobo don't startup...
Now I'm thinking buy a H81 Pro BTC, if the mobo let's the user connect the cards without connect the molex...
Well, now waiting for a new mobo
