Figure 4. Processor Thermal Characterization Parameter Relationships - Intel QX9770 - Core 2 Extreme Quad-Core Processor Design Manual

The case-to-local ambient thermal characterization parameter of the processor, Ψ
comprised of Ψ
and of Ψ
Ψ = Ψ
CA
Where:
Ψ
CS
Ψ
SA
Ψ is strongly dependent on the thermal conductivity and thickness of the TIM
CS
between the heatsink and IHS.
Ψ is a measure of the thermal characterization parameter from the bottom of the
SA
heatsink to the local ambient air. Ψ
conductivity, and geometry. It is also strongly dependent on the air velocity through
the fins of the heatsink.
Figure 4 illustrates the combination of the different thermal characterization
parameters.

Figure 4. Processor Thermal Characterization Parameter Relationships

Heatsink Heatsink
Processor Processor
24
, the thermal interface material thermal characterization parameter,
CS
, the sink-to-local ambient thermal characterization parameter:
SA
+ Ψ
(Equation 2)
CS SA
= Thermal characterization parameter of the thermal interface material
(°C/W)
= Thermal characterization parameter from heatsink-to-local ambient
(°C/W)
TIM TIM
IHS IHS
LGA775 Socket Heatsink Loading
is dependent on the heatsink material, thermal
SA
T T
A A
T T
S S
T T
C C
Thermal and Mechanical Design Guidelines
, is
CA
Ψ Ψ
CA CA
LGA775 Socket LGA775 Socket
System Board System Board