Boxed Processor Specifications
Table 7-2. Fan Heatsink Power and Signal Specifications
Boxed Processor Fan
Heatsink Set Point (ºC)
Boxed Processor Fan Speed
Notes
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
X ≤ 30
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.
Y = 34
-
-
When the internal chassis temperature is above or equal to this set point,
the fan operates at its highest speed.
Z ≥ 38
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
Table 7-1) and remote thermal diode measurement 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 temperature
diode (T
). Fan RPM is modulated through the use of an ASIC located on the motherboard that
diode
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 heat sink 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
®
®
Intel Pentium 4 Processor on 90 nm Process in the 775-Land Package Thermal Design Guide.
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Datasheet
INTEL [ INTEL ]
