Intel Pentium D 945 HH80553PG0964MN User Manual

109

NOTES:
1.

Set point variance is approximately ±1°C from Thermal Module Assembly to Thermal 
Module Assembly.

If the boxed processor TMA 4-pin connector is connected to a 4-pin motherboard 

header and the motherboard is designed with a fan speed controller with PWM output 

(see CONTROL in 

) and remote thermal diode measurement capability, the 

boxed processor will operate as described in the following paragraphs.

As processor power has increased, the required thermal solutions have generated 

increasingly more noise. Intel has added an option to the boxed processor that allows 

system integrators to have a quieter system in the most common usage. 

The 4-wire PWM controlled fan in the TMA solution provides better control over chassis 

acoustics. It allows better granularity of fan speed and lowers overall fan speed than a 

voltage-controlled fan. Fan RPM is modulated through the use of an ASIC located on 

the motherboard that sends out a PWM control signal to the 4

th

 pin of the connector 

labeled as CONTROL. The fan speed is based on a combination of actual processor 

temperature and thermistor temperature. 

If the 4-wire PWM controlled fan in the TMA solution is connected to a 3-pin baseboard 

processor fan header it will default back to a thermistor controlled mode, allowing 

compatibility with existing 3-pin baseboard designs. Under thermistor controlled mode, 

the fan RPM is automatically varied based on the T

inlet

 temperature measured by a 

thermistor located at the fan inlet.

For more details on specific motherboard requirements for 4-wire based fan speed 

control see the Intel

X ≤ 23

When the internal chassis temperature is below or equal to this 
set point, the fan operates at its lowest speed. Recommended 
maximum internal chassis temperature for nominal operating 
environment.

1

Y = 29

When the internal chassis temperature is at this point, the fan 
operates between its lowest and highest speeds. 
Recommended maximum internal chassis temperature for 
worst-case operating environment.

 Z ≥ 35.5

When the internal chassis temperature is above or equal to this 
set point, the fan operates at its highest speed.

1