Asus P5N72-T Premium - Manual (Page 59)

ASUS P5N72-T Premium 2-33
6. CPU and chassis fan connectors (4-pin CPU_FAN, 3-pin CHA_FAN1–3)
The fan connectors support cooling fans of 350 mA–1000 mA (24 W max.) or
a total of 1 A–3.48 A (41.76 W max.) at +12V. Connect the fan cables to the
fan connectors on the motherboard, making sure 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!
If you install two VGA cards, we recommend that you plug the chassis fan
cable to the motherboard connector labled CHA_FAN1 or CHA_FAN2 for better
thermal environment.