Asus Crosshair V Formula/ThunderBolt - Manual (Page 52)

Never connect a 1394 cable to the USB connectors. Doing so will damage the
motherboard!
4.. USB.3.0.connectors.(18-1.pin.USB3_56)
These connectors are for USB 3.0 ports. Connect the USB 3.0 module cables
to these connectors, then install the modules to slots opening at the back of
the system chassis.
You can connect the USB 2.0 cable to ASUS Q-Connector (USB, blue) first, and
then install the Q-Connector (USB) to the USB 2.0 connector onboard.
2-22 Chapter 2: Hardware information