Asus Rampage III Formula - Manual (Page 71)

7. Thermal sensor cable connectors (2-pin OPT_TEMP1/2/3)
These connectors are for temperature monitoring. Connect the thermal
sensor cables to these connectors and place the other ends to the devices
which you want to monitor temperature. The optional fan1/2/3 can work with
the temperature sensors for a better cooling effect.
Enable OPT FAN1/2/3 overheat protection in BIOS if you connect thermal
sensor cables to these connectors.
8. Digital audio connector (4-1 pin SPDIF_OUT)
This connector is for an additional Sony/Philips Digital Interface (S/PDIF)
port(s). Connect the S/PDIF Out module cable to this connector, then install
the module to a slot opening at the back of the system chassis.
The thermal sensor cable is purchased separately and is included in the
package only on selected models.
ROG Rampage III Formula 2-43