Fan Heatsink Power Supply
The boxed processor's fan heatsink requires a +12V power supply. A fan power cable will
be shipped with the boxed processor to draw power from a power header on the
motherboard. The power cable connector and pinout are shown in Figure 35.
Motherboards must provide a matched power header to support the boxed processor.
Table 37 contains specifications for the input and output signals at the fan heatsink
connector. The fan heatsink outputs a SENSE signal, which is an open-collector output
that pulses at a rate of two pulses per fan revolution. A motherboard pull-up resistor
provides VOH to match the system board-mounted fan speed monitor requirements, if
applicable. Use of the SENSE signal is optional. If the SENSE signal is not used, pin 3 of
the connector should be tied to GND.