Asus P5G41T-M/USB3 - Manual (Page 30)

1-20 Chapter 1: Product introduction
2. CPU and chassis fan connectors (4-pin CPU_FAN, 3-pin CHA_FAN)
Connect the fan cables to the fan connectors on the motherboard, ensuring that the
black wire of each cable matches the ground pin of the connector.
Do not forget to connect the fan cables to the fan connectors. Insufficient air flow inside the
system may damage the motherboard components. These are not jumpers! Do not place
jumper caps on the fan connectors!
Only the 4-pin CPU fan supports the ASUS Q-FAN feature.
3. Digital audio connector (4-1 pin SPDIF_OUT)
This connector is for an additional Sony/Philips Digital Interface (S/PDIF) port. 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 S/PDIF module is purchased separately.