This book contributes the thoroughly refereed post-proceedings of the 4th International Workshop on Power-Aware Computer Systems, PACS 2004, held in Portland, OR, USA in December 2004.

The 12 revised full papers presented were carefully reviewed, selected, and revised for inclusion in the book. The papers span a wide spectrum of topics in power-aware systems; they are organized in topical sections on microarchitecture- and circuit-level techniques, power-aware memory and interconnect systems, and frequency- and voltage-scaling techniques.