Intel W3680 AT80613003543AF Data Sheet

101

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 

, 

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 

) 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 

 for the specific requirements.

Lower Set Point

Lowest Noise Level

Internal Chassis Temperature (Degrees C)

X

Y

Z

Increasing Fan
Speed & Noise

Higher Set Point

Highest Noise Level