Intel 4 662 HH80547PG1042MH Data Sheet

105

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 

) 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

th

 wire PWM solution provides better control over chassis acoustics. This is achieved by 

more accurate measurement of processor die temperature through the processor’s temperature 
diode (T

DIODE

). 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 new 4-pin active TMA solution is connected to an older 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

§