Intel X5365 Design Guide - Page 49

Thermal/Mechanical Reference Design 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 2-8. Table 2-8. CEK Heatsink Thermal Mechanical Characteristics Size 2U+ 1U Height (mm) [in.] 50.80 [2.00] 27.00 [1.06] Weight Target Airflow Through Fins Mean Ψca Standard Deviation Ψca (kg) [lbs] (m3/hr) [CFM] (°C/W) (°C/W) 1.0 [2.2] 0.53 [1.2] 45.9 [27] 25.5 [15] 0.180 0.243 0.0033 0.0023 Pressure Drop (Pa) [in H2O] 45.3 [0.182] 82.4 [0.331] 2.4.7.2 Thermal 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 2-9. Recommended Thermal Grease Dispense Weight Processor TIM Dispense weight Minimum Maximum 400 Units mg TIM loading provided 18 30 lbf by CEK 80 133 N Notes Shin-Etsu* G751. Dispense weight is an approximate target. Generated by the CEK. 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 133N [30 lbf] on the TIM to improve the thermal performance. Quad-Core Intel® Xeon® Processor 5300 Series Thermal/Mechanical Design Guidelines (TMDG) 49