Does anyone know if the USB 3.0 add-in cards will work if I don't connect a molex adapter? I'm trying to add one to a server build that does not have any way to add a 4-pin molex. The hard drives I would be attaching have their own power supplies, so I don't think I need the extra power to be supplied via USB.
I think it all depends on how the add in card is passing ground along. If its from the pci/pcie slot then I think it would work but if its from the molex then you probably would wind up with a poor quality signals on the data lines which may affect speeds. You might have to refer to the manufacturer unless you want to do trial and error. Let us know how you make out.