Dual-Core Intel® Xeon® Processor 3000 Series Datasheet 101
Boxed Processor Specifications
7.3.2 Variable Speed Fan
If the boxed processor fan heatsink 4-pin connector is connected to a 3-pin
motherboard header it will operate as follows:
The boxed processor fan will operate at different speeds over a short range of internal
chassis temperatures. This allows the processor fan to operate at a lower speed and
noise level, while internal chassis temperatures are low. If internal chassis temperature
increases beyond a lower set point, the fan speed will rise linearly with the internal
temperature until the higher set point is reached. At that point, the fan speed is at its
maximum. As fan speed increases, so does fan noise levels. Systems should be
designed to provide adequate air around the boxed processor fan heatsink that remains
cooler then lower set point. These set points, represented in Figure 7-9 and Table 7-2,
can vary by a few degrees from fan heatsink to fan heatsink. The internal chassis
temperature should be kept below 38 ºC. Meeting the processor's temperature
specification (see Chapter 5) is the responsibility of the system integrator.
The motherboard must supply a constant +12 V to the processor's power header to
ensure proper operation of the variable speed fan for the boxed processor. Refer to
Table 7-1 for the specific requirements.
Figure 7-9. Boxed Processor Fan Heatsink Set Points
Lower Set Point
Lowest Noise Level
Internal Chassis Temperature (Degrees C)
X
YZ
Increasing Fan
Speed & Noise
Higher Set Point
Highest Noise Level
