Nvidia NFORCE 780I SLI - Manual (Page 32)

780i 3-Way SLI Motherboard
NVIDIA Corporation
22 October 17, 2007 | DU-03597-001_v01
There are four more fan connectors on the motherboard. For this installation,
these will not be used.
COM1
The motherboard kit provides an additional serial COM header for your
machine. Connect one side of a switching cable to the header and then attach
the serial COM device to the other side of the cable.
System fan
connector
Auxiliary fan
connector
Auxiliary fan connector
Auxiliary fan
connector
Fan Connector
3 2
1
GND
+12V
SENSE