Intel 5400 Series Thermal Interface Material TIM, CEK Heatsink Thermal Mechanical Characteristics

Thermal/Mechanical Reference Design

Although the CEK heatsink fits into the legacy volumetric keep-in, it has a larger footprint due to the elimination of retention mechanism and clips used in the older enabled thermal/mechanical components. This allows the heatsink to grow its base and fin dimensions, further improving the thermal performance. A drawback of this enlarged size and use of copper for both the base and fins is the increased weight of the heatsink. The retention scheme employed by CEK is designed to support heavy heatsinks (approximately up to 1000 grams) in cases of shock, vibration and installation as explained in Appendix E. Some of the thermal and mechanical characteristics of the CEK heatsinks are shown in Table 2-7.

Table 2-7. CEK Heatsink Thermal Mechanical Characteristics

	Height	Weight	Target	Mean Ψca	Standard	Pressure Drop
Size			Airflow
					Deviation Ψca
			Through Fins
	(mm) [in.]	(kg) [lbs]	(m3/hr)	(°C/W)	(°C/W)	(Pa) [in H2O]
			[CFM]
2U+	50.80 [2.00]	1.0 [2.2]	45.9 [27]	0.177	0.0033	45.3 [0.182]
1U	27.00 [1.06]	0.53 [1.2]	25.5 [15]	0.240	0.0023	82.4 [0.331]

2.5.7.2Thermal Interface Material (TIM)

A TIM must be applied between the package and the heatsink to ensure thermal conduction. The CEK reference design uses Shin-Etsu G751 thermal grease.

The recommended grease dispense weight to ensure full coverage of the processor IHS is given below. For an alternate TIM, full coverage of the entire processor IHS is recommended.

Table 2-8. Recommended Thermal Grease Dispense Weight

Processor	Minimum	Maximum	Units	Notes
TIM Dispense weight		400	mg	Shin-Etsu* G751. Dispense
				weight is an approximate target.
TIM loading provided	18	30	lbf	Generated by the CEK.
by CEK	80	133	N

It is recommended that you use thermally conductive grease. Thermally conductive grease requires special handling and dispense guidelines. The following guidelines apply to Shin-Etsu G751 thermal grease. For guidance with your specific application, please contact the vendor. Vendor information is provided in Appendix F. The use of a semi-automatic dispensing system is recommended for high volume assembly to ensure an accurate amount of grease is dispensed on top of the IHS prior to assembly of the heatsink. A typical dispense system consists of an air pressure and timing controller, a hand held output dispenser, and an actuation foot switch. Thermal grease in cartridge form is required for dispense system compatibility. A precision scale with an accuracy of ±5 mg is recommended to measure the correct dispense weight and set the corresponding air pressure and duration. The IHS surface should be free of foreign materials prior to grease dispense.

Additional recommendations include recalibrating the dispense controller settings after any two hour pause in grease dispense. The grease should be dispensed just prior to heatsink assembly to prevent any degradation in material performance. Finally, the thermal grease should be verified to be within its recommended shelf life before use.

The CEK reference solution is designed to apply a compressive load of up to 133 N [30 lbf] on the TIM to improve the thermal performance.

Quad-Core Intel® Xeon® Processor 5400 Series TMDG 47