I just purchased a Sabrent usb 3.0 2 port pci card, and noticed that it has a 3 or 4 pin , small connector , Does this card need a power connection or is connecting to the motherboard enough?  If it does need connected to the power supply, is there a extra power cable not being used ? It only came with the card and driver cd. I have a xps 420. Also, what is the best way to test the card to see if it is working like it should. ? Thanks