The opportunities for optimizing a design for power are greatest at the architectural level of abstraction, where the design architecture is determined. The further a design moves downstream the less effective optimization techniques become. Power optimization must begin at the electronic system level (ESL). Vista™ offers architectural analysis, exploration, and optimization of performance and power at the ESL. It features unique power modeling capabilities and a wide range of power analysis toolsets. Combining Vista with Catapult® creates a continuous power optimization path from the system level through synthesis to implementation. This flow and its benefits are described in this paper, along with a demonstration of using power policies to evaluate the effect of different architectural choices on power consumption.