Example; Processor Thermal Solution Performance Assessment - Intel Q9450 - Core 2 Quad Quad-Core Processor Design Manual

Thermal Metrology
3.1.1

Example

The cooling performance, 
characterization parameter described above:
 The case temperature T
datasheet.
 Define a target local ambient temperature at the processor, T
Since the processor thermal profile applies to all processor frequencies, it is important
to identify the worst case (lowest 
establish a design strategy.
The following provides an illustration of how one might determine the appropriate
performance targets. The example power and temperature numbers used here are not
related to any specific Intel processor thermal specifications, and are for illustrative
purposes only.
Assume the TDP, as listed in the datasheet, is 100 W and the maximum case
temperature from the thermal profile for 100W is 67 °C. Assume as well that the
system airflow has been designed such that the local ambient temperature is 38 °C.
Then the following could be calculated using equation 1 from above:
 = (T
CA
To determine the required heatsink performance, a heatsink solution provider would
need to determine 
configuration. If the heatsink solution were designed to work with a TIM material
performing at 
the heatsink would be:
 = 
SA
3.2 Processor Thermal Solution Performance
Assessment
Thermal performance of a heatsink should be assessed using a thermal test vehicle
(TTV) provided by Intel. The TTV is a stable heat source that the user can make
accurate power measurement, whereas processors can introduce additional factors
that can impact test results. In particular, the power level from actual processors
varies significantly, even when running the maximum power application provided by
Intel, due to variances in the manufacturing process. The TTV provides consistent
power and power density for thermal solution characterization and results can be
easily translated to real processor performance.
Once the thermal solution is designed and validated with the TTV, it is strongly
recommended to verify functionality of the thermal solution on real processors and on
fully integrated systems. The Intel maximum power application enables steady power
dissipation on a processor to assist in this testing.
Thermal and Mechanical Design Guidelines
is then defined using the principle of thermal
CA,
and thermal design power TDP given in the processor
C-MAX
– T ) / TDP = (67 – 38) / 100 = 0.29 °C/W
C, A
performance for the selected TIM and mechanical load
CS
 0.10 °C/W, solving for equation 2 from above, the performance of
CS
  = 0.29  0.10 = 0.19 °C/W
CA CS
) for a targeted chassis characterized by T
CA
.
A
to
A
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