Asus M3N72-D - Manual (Page 58)

2-34 Chapter 2: Hardware information
6. CPU, chassis, and power fan connectors (4-pin CPU_FAN, 3-pin
CHA_FAN1, 3-pin PWR_FAN)
The fan connectors support cooling fans of 350 mA~2000 mA (24 W max.)
or a total of 1 A~7 A (84 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!
• Only the CPU_FAN and CHA_FAN 1 connectors support the ASUS
Q-FAN 2 feature.
• If you install two graphics cards, we recommend that you plug the rear
chassis fan cable to the motherboard connector labeled CHA_FAN1 for
better thermal environment.