Intel QX6700 HH80562PH0678M User Manual

94

Datasheet

The boxed processor fan heatsink is designed to operate continuously at full speed to 

allow maximum user control over fan speed. The fan speed can be controlled by 

hardware and software from the motherboard. This is accomplished by varying the duty 

cycle of the Control signal on the 4th pin (see 

). The motherboard must have a 

4-pin fan header and must be designed with a fan speed controller with PWM output 

and Digital Thermometer measurement capabilities. For more information on specific 

motherboard requirements for 4-wire based fan speed control refer to the appropriate 

Thermal and Mechanical Design Guidelines (see 

).

The Internal chassis temperature should be kept below 39 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 fan for the boxed processor.  See 

 for specific 

requirements. 

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.