Alright so i'm pretty good at computers, but, I am thinking of building my computer and i'm not sure what to do. I saw some builds include a 'USB 3.0 Cable' don't usb's come from the motherboard? Do you need to plug it in just to use one from the motherboard? Or do you only plug in usb's from the front of the case. I really am not sure and I'd like something very specific on how to get usb's to work. Since, I'm deciding against a new motherboard but confuses me with its Usb 3.0.