1. Thermal Simulation Discussion
7/5/2017
Yueming Li, Thermal Engineer, Facebook
John Fernandes, Thermal Engineer, Facebook
Jia Ning, Hardware Engineer, Facebook

2. A-Cases Update Updated models for A cases
Updated Mezz 3.0 Case A1 WO HS.pdml (cold-aisle)
Updated Mezz 3.0 Case A6 WO HS.pdml (hot-aisle)
Corrected QSFP model to minimize heat conduction from cage to PCB; corrected Mezz PCB sizes
Comparison between with and without QSFP heat sinks for both normal operation and stand-by cases

3. Improving QSFP Cooling – MLX HS
Cold Aisle – Normal Operation
Cold Aisle – Stand-by Condition
Adding HS can reduce the temperature of I/O modules by ~4-6 °C for cold-aisle cases.
ASIC temperature will increase by ~3-7°C due to higher impedance.

4. Improving QSFP Cooling – MLX HS
Hot Aisle – Normal Operation
Hot Aisle – Stand-by Condition
Adding HS can reduce the temperature of I/O modules for hot-aisle cases but not enough to pass.

5. Impact of Contact Resistance
A few cases were studied
Contact resistance can account for up to 5°C of the thermal budget

6. Discussion Topics
Wind tunnel specification for vendors to share test data with adopters
Feedback from the last meeting
Definition of monitor points are important
Wind tunnel setup should provide consistent results
Request to community
Share ideas/thoughts on wind tunnel specification
Integrate shared PDMLs in system thermal models to better understand impact of current design(s)