Nvidia NFORCE 680I - Manual (Page 31)

Fan Connections
There are two types of fan connections, the 3-pin system fan and the 4-pin CPU fan. The
fan speed can be detected and viewed in the PC Health Status section of the CMOS
Setup. Both types of fans are automatically turned off after the system enters S3, S4 and
S5 mode.
22
Installing and Configuring the BFG NVIDIA nForce 680i LT SLI Motherboard
Note that the CPU fan cable can be either a 3-pin
or a 4-pin connector. Connect a 3-pin connector
to pins 1, 2, and 3 on the motherboard connector.
CPU Fan Connector
4 3 2 1
GND SENSE
PWR CONTROL
Fan Connectors
3 2 1
GND
+12V
SENSE