Intel Xeon E5405 BX80574E5405 User Manual

Product codes
BX80574E5405
Page of 100
Thermal/Mechanical Reference Design
38
Quad-Core Intel® Xeon® Processor 5400 Series TMDG
2.5.2
Thermal Interface Material
TIM application between the processor IHS and the heatsink base is generally required 
to improve thermal conduction from the IHS to the heatsink. Many thermal interface 
materials can be pre-applied to the heatsink base prior to shipment from the heatsink 
supplier and allow direct heatsink attach, without the need for a separate TIM dispense 
or attach process in the final assembly factory.
All thermal interface materials should be sized and positioned on the heatsink base in a 
way that ensures the entire processor IHS area is covered. It is important to 
compensate for heatsink-to-processor attach positional alignment when selecting the 
proper TIM size.
When pre-applied material is used, it is recommended to have a protective application 
tape over it. This tape must be removed prior to heatsink installation.
The TIM performance is susceptible to degradation (i.e. grease breakdown) during the 
useful life of the processor due to the temperature cycling phenomena. For this reason, 
the measured T
CASE
 value of a given processor can decrease over time depending on 
the type of TIM material.
Refer to 
 for information on the TIM used in the Intel reference heatsink 
solution.
2.5.3
Summary
In summary, considerations in heatsink design include: 
• The local ambient temperature T
LA
 at the heatsink, airflow (CFM), the power being 
dissipated by the processor, and the corresponding maximum T
CASE
 temperature. 
These parameters are usually combined in a single lump cooling performance 
parameter, Ψ
CA
 (case to air thermal characterization parameter). More information 
on the definition and the use of Ψ
CA
 is given in 
.
• Heatsink interface (to IHS) surface characteristics, including flatness and 
roughness.
• The performance of the TIM used between the heatsink and the IHS.
• Surface area of the heatsink.
• Heatsink material and technology.
• Development of airflow entering and within the heatsink area.
• Physical volumetric constraints placed by the system.
• Integrated package/socket stackup height information is provided in the LGA771 
Socket Mechanical Design Guide.