Thermal solution development for high-end server systems

A methodology to develop a thermal solution was demonstrated through a case study of upgrading processors in an existing cabinet, thereby increasing the power envelope of the processors. The Sun Fire E25K server, based on UltraSparc IV (USIV), was used as an example in this paper. This high-end server utilized the same physical configuration as in the preceding generation Sun Fire 15K server accommodating seventy-two UltraSparc III (USIII) processors. Extensive experimental investigations have been carried out to characterize the thermal performance in the Sun Fire 15K including cabinet-level, board-level, CPU air-cooled heat sink, and fan/fan tray thermal characterization. Solutions were proposed by combining the experimental data with flow network modeling, validated analytical methods and numerical modeling. Solutions included a new CPU heat sink design and air flow optimization at the board and cabinet level. The proposed solutions were verified in the existing product and successfully implemented in the new product.