Asus Rampage II Extreme - Manual (Page 63)

7. CPU, chassis, power and optional fan connectors
(4-pin CPU_FAN, 3-pin CHA_FAN1-3, 3-pin PWR_FAN, 3-pin OPT_FAN1–3)
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, CHA_FAN1–3, and OPT_FAN1–3 connectors support
the ASUS Fan Xpert feature.
• If you install two VGA cards, we recommend that you plug the chassis
fan cable to the motherboard connector labled OPT_FAN1/2/3 for better
thermal environment.
ROG Rampage II Extreme 2-35