The motherboard manual States: USB 2.0 header while the corsair says, to plug it into an available internal USB 2.0 header. Does it qualify as an internal usb header?If the cable your case comes in says it's USB or USB2.0, and your motherboard has a USB2.0 header, they will go together and you'll be fine.
1394 is Firewire. It's largely obsolete now and I think the warning is for if your motherboard has a 1394 Firewire header. In which case, DON'T plug in a USB2.0 cable into a 1394 header, that's all. It matters because the headers look practically identical.
That's exactly what the instructions meant.The motherboard manual States: USB 2.0 header while the corsair says, to plug it into an available internal USB 2.0 header. Does it qualify as an internal usb header?