Thermal management of Fujitsu's high-performance servers

With the continued increase in power dissipation and power density of high-performance microprocessors, as well as requirements for high-density packaging and lower device junction temperatures, improvements of electronic cooling technologies have been becoming strategically important in the challenge of advanced thermal solutions for achieving higher cooling efficiencies while meeting reliability, packaging, cost, and environmental requirements appropriate to various electronic equipments. This paper gives an overview of thermal design and cooling technology development for Fujitsu's high-performance servers, using the latest high-end UNIX server PRIMEPOWER 2500 as an example. The thermal management is outlined from viewpoints of the server cabinet, system board, and CPU package. It also discusses the challenges in cooling technology developments arising from thermal management of high-density and asymmetric CPU power dissipation, investigations of thermal interface and heat spreading materials, and enhancements of heatsink cooling capabilities.