An overview of system packaging and thermal management of the Fujitsu high-performance Unix server PRIMEPOWER HPC2500 is introduced in the present paper. Each node of the HPC2500 comprises sixteen system boards containing up to 128 SPARC64V CPU processors, with the maximum power dissipation about 30kW. A full configuration of the HPC2500 can be further scaled up to the maximum of 128 nodes, resulting in 16,384 CPU processors installed. Thermal management is introduced from viewpoints of the server-cabinet, system-board and CPU processor module levels, respectively. A design strategy of the forced convection air cooling scheme is outlined, implemented to meet increased demanding requirements of high density packaging, high power and power-density dissipations. Furthermore, thermal challenges, arising from high asymmetric power distributions and dissipations of CPU processors, are investigated for high performance computers. Temperature distributions of the CPU processors, effects of heat spreading materials (HIS) and impacts of thermal interface materials (TIM) on the cooling and packaging designs are also analysed and illustrated.
