The Intel® Core™ Duo processor is the first mobile processor that uses Chip Multi-Processing (CMP) on-die technology to maximize performance and minimize power consumption. This paper provides an overview of the power control unit and its impact on the power-saving mechanisms. We describe the distribution of P-states and look at other techniques used to improve the system power consumption including the impact of multi-threading on power consumption. Then, we provide recommendations on optimizing for CMP and building power-friendly applications.