Asus Motherboard A8N-SLI Premium - Manual (Page 36)

2-10 Chapter 2: Hardware information
3. When the fan and heatsink assembly is in place, connect the CPU fan
cable to the connector on the motherboard labeled CPU_FAN.
Do not forget to connect the CPU fan connector! Hardware monitoring
errors can occur if you fail to plug this connector.
A8N-SLI PREMIUM
®
A8N-SLI PREMIUM CPU fan connector
CPU_FAN
GND Rotation +12V