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Table 31.
Fan Heatsink Power and Signal Specifications
Boxed Processor
Fan Heatsink
Set Point (°C)
X
Y = 35
Z
NOTES:
1. Set point variance is approximately ± 1 C from fan heatsink to fan heatsink.
If the boxed processor fan heatsink 4-pin connector is connected to a 4-pin
motherboard header and the motherboard is designed with a fan speed controller with
PWM output (CONTROL see
capability, the boxed processor will operate as follows:
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 4th wire PWM solution provides better control over chassis acoustics. This is
achieved by more accurate measurement of processor die temperature through the
processor's Digital Thermal Sensors (DTS) and PECI. Fan RPM is modulated through the
use of an ASIC located on the motherboard that sends out a PWM control signal to the
4th pin of the connector labeled as CONTROL. The fan speed is based on actual
processor temperature instead of internal ambient chassis temperatures.
If the new 4-pin active fan heatsink 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 Tinlet 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 appropriate Thermal and Mechanical Design Guidelines (see
Section
1.2).
98
When the internal chassis temperature is below or equal to this set
point, the fan operates at its lowest speed. Recommended
30
maximum internal chassis temperature for nominal operating
environment.
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.
When the internal chassis temperature is above or equal to this set
38
point, the fan operates at its highest speed.
Table
Boxed Processor Fan Speed
30) and remote thermal diode measurement
§
Boxed Processor Specifications
Notes
1
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Datasheet
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