Thermal Solution Performance Versus Fan Speed - Intel Core i7-800 Specifications

Sensor Based Thermal Specification Design Guidance
7.3.3.2 Thermal Solution Characterization for Fan Speed Control
The final step in thermal solution validation is to establish the thermal solution
performance,Ψ
allow the fan speed control algorithm developer to program the device. It also is
needed to asses the expected acoustic impact of the processor thermal solution in the
system.
The characterization data should be taken over the operating range of the fan. Using
the RCBF7-1156 (DHA-A) as the example the fan is operational from 900 to 3150 RPM.
The data was collected at several points and a curve was fit to the data see
Taking data at 6 evenly distributed fan speeds over the operating range should provide
enough data to establish an equation. By using the equation from the curve fitting a
complete set of required fan speeds as a function of Ψ
from the reference thermal solution characterization are provided in
The fan speed control device may modulate the thermal solution fan speed (RPM) by
one of two methods. The first and preferred is pulse width modulation (PWM) signal
compliant with the 4-Wire Pulse Width Modulation (PWM) Controlled Fans specification.
the alternative is varying the input voltage to the fan. As a result the characterization
data needs to also correlate the RPM to PWM or voltage to the thermal solution fan. The
fan speed algorithm developer needs to associate the output command from the fan
speed control device with the required thermal solution performance as stated in
Table 7-1. Regardless of which control method is used, the term RPM will be used to
indicate required fan speed in the rest of this document.
Note: When selecting a thermal solution from a thermal vendor, the characterization data
should be requested directly from them as a part of their thermal solution collateral.
Figure 7-5.

Thermal Solution Performance versus Fan Speed

Note: This data is taken from the preliminary evaluation of the validation of the RCBF7-1156 (DHA-A)
reference processor thermal solution. The Ψ
this chapter.
Thermal/Mechanical Specifications and Design Guidelines
and acoustics as a function of fan speed. This data is necessary to
CA
be developed. The results
CA
versus RPM data is available in
CA
Figure 7-5.
Table 7-1.
Table 7-1 at the end of
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