Intel Core 2 Duo E7300 BX80570E7300 User Manual

Thermal and Mechanical Design Guidelines   

 43 

The TMA must fulfill the processor cooling requirements shown in Table 

5–1 when it is 

installed in a functional BTX system. When installed in a system, the TMA must 

operate against the backpressure created by the chassis impedance (due to vents, 

bezel, peripherals, etc…) and will operate at lower net airflow than if it were tested 

outside of the system on a bench top or open air environment. Therefore an allowance 

must be made to accommodate or predict the reduction in Thermal Module 

performance due to the reduction in heatsink airflow from chassis impedance. For this 

reason, it is required that the Thermal Module satisfy the prescribed 

CA 

requirements 

when operating against an impedance that is characteristic for BTX platforms.  

Because of the coupling between TMA thermal performance and system impedance, 

the designer should understand the TMA effective fan curve. This effective fan curve 

represents the performance of the fan component AND the impedance of the stator, 

heatsink, duct, and flow partitioning devices. The BTX system integrator will be able to 

evaluate a TMA based on the effective fan curve of the assembly and the airflow 

impedance of their target system. 

Note:  It is likely that at some operating points the fans speed will be driven by the system 

airflow requirements and not the processor thermal limits. 

5-1 shows the effective fan curve for the reference design TMA. These curves 

are based on analysis. The boundary conditions used are the S2 6.9L reference 

chassis, the reference TMA with the flow partitioning device, extrusion and an AVC 

Type II fan geometry. 

When selecting a fan for use in the TMA care should be taken that similar effective fan 

curves can be achieved. Final verification requires the overlay of the Type II MASI 

curve to ensure thermal compliance.