This is a fantastic solution if the power supply has no more outgoing connections.(Molex wires)This is exactly the same wire you'd get if you bought a power supply for your computer.(quality wise)If you are new to building computers make sure you press the end connectors hard enough for the pins to go in correctly.
I bought 2 of these cables and they were a little stiff, not a problem you just need to make sure they fully connect. These cables are great for adding a usb 3.0-pci 1.0 express card. You can also use these for other components though.
I used mine to setup a usb 3.0 card, I simply unplugged 1 outgoing wire from power supply to fan, placed this wire on the outgoing power supply, this gives you 2 connections. 1 for the fan and the other for the usb 3.0 pci card. It is that simple.