The Intel^® Core™ Duo processor is the first mobile processor to implement Chip Multi-Processing (CMP), also known as dual core-on-die. This first implementation was carefully chosen to deliver maximum performance for a given power. The performance improvement was achieved by enhancing the single-core micro-architecture, which results in better single- threaded performance, and by implementing CMP, which improves the performance of multi-threaded applications and parallel application processing. The focus of this paper is to introduce the reader to the CMP aspects of the Intel Core Duo processor. Since the Intel Core Duo processor was designed to be a mobile processor, we examine in detail the design considerations that had to be taken into account to achieve a balance between performance improvements and power savings, and we provide recommendations on optimizing the code developed for the Intel Core Duo processor so that future applications can take full advantage of the new design.