Do I have a power sharing problem, or a bad riser card???

I am running the Asus Crosshair VI Hero mobo, and am using every pcie slot except for 1.1, the very top x1 slot. My question is this, bc the CH6 only comes with one usb 3.0 header on the board, and my case has four usb 3.0 ports on the front I/O plate, I needed another header. So I ordered a pcie riser card, with a 3.0 header. But although I have it hooked up correct, those two usb 3.0 ports are not working on the front of my case. So I am wondering if I have a bad card, or if using so many of the pcie slots has killed the power to this card??? Thanks for any help.