Abstract: In CPU speed scaling systems, execution speed can be adjusted dynamically under operating system control to provide controlled tradeoffs between response time, fairness, and energy consumption. In prior work, we proposed Decoupled Speed Scaling as one possible approach to achieve optimality, fairness, and robustness in a speed scaling system. In more recent work, we proposed a second approach, called Envelope-based Turbocharging. We evaluate both of these approaches using analysis and simulation. Our results show that Envelope-based Turbocharging can provide response time performance that is comparable to Decoupled Speed Scaling, albeit with slightly higher energy costs. Our ongoing work is focused on an experimental environment for the practical evaluation of speed scaling strategies. Biography: Carey Williamson is Professor and Head in the Department of Computer Science at the University of Calgary. He holds a B.Sc.(Honours) degree in Computer Science from the University of Saskatchewan in 1985, and a Ph.D. in Computer Science from Stanford University in 1992. Dr. Williamson's research interests include Internet protocols, wireless networks, network traffic measurement, workload characterization, network simulation, and Web server performance.