64-bit server cooling requirements

Cooling of 64-bit servers is constrained by increasing power and decreasing space. Power dissipation of high performance processors is predicted to increase linearly over the next decade. Thermal interface, heat spreading and heatsink-to-ambient convection each provide similar resistances in the thermal path from chip to ambient. One departure from previous practice will be the increasing sensitivity of power dissipation with junction temperature. As leakage current, previously a small contribution to total power dissipation, becomes significant, chip power dissipation will become a stronger function of temperature. Expenditure of energy on enhanced cooling, such as pumped water or vapor-cycle refrigeration, may result in reduced total system power. Recent advances in thermoelectrics could change many assumptions in refrigeration, enabling distributed and localized refrigeration at the processor level with minimum space requirements.