Intel Core 2 Duo E7300 BX80570E7300 User Manual

Thermal and Mechanical Design Guidelines   

 29 

Assume the TDP, as listed in the datasheet, is 100 W and the maximum case 

temperature from the thermal profile for 100 W 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: 



CA

 = (T

C,

  T

A

) / TDP = (67 – 38) / 100 = 0.29° C/W 

To determine the required heatsink performance, a heatsink solution provider would 

need to determine 

CS

 performance for the selected TIM and mechanical load 

configuration. If the heatsink solution were designed to work with a TIM material 

performing at 

CS

  0.10° C/W, solving for equation 2 from above, the performance of 

the heatsink would be:  



SA

 = 

CA

  

CS

 = 0.29  0.10 = 0.19° C/W 

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. Accurate measurement of the power 

dissipated by an actual processor is beyond the scope of this document.  

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. This maximum power application is 

provided by Intel. 

The local ambient temperature T

A

 is the temperature of the ambient air surrounding 

the processor. For a passive heatsink, T

A

 is defined as the heatsink approach air 

temperature; for an actively cooled heatsink, it is the temperature of inlet air to the 

active cooling fan. 

It is worthwhile to determine the local ambient temperature in the chassis around the 

processor to understand the effect it may have on the case temperature.  

T

A

 is best measured by averaging temperature measurements at multiple locations in 

the heatsink inlet airflow. This method helps reduce error and eliminate minor spatial 

variations in temperature. The following guidelines are meant to enable accurate