IBM POWER9 is a family of processor chips designed to serve a diverse set of workloads. New features have been added to POWER9 to address emerging workloads such as cognitive and artificial intelligence applications. POWER9 also further enhances features introduced in IBM POWER8 for big data and cloud applications. Distinct chips using common intellectual property building blocks are provided to enable enterprise applications requiring large symmetric multiprocessor servers with large memory footprints, as well as one to two socket industry form-factor servers. In this paper, we describe new POWER9 features for both system types. Several highly differentiated new features are described in other papers in this issue of the IBM Journal, and they provide a more in-depth description of their unique design aspects.