The present document specifies a metric using the Server Efficiency Rating Tool (SERT™), test conditions and product family configuration for the assessment of energy efficiency of computer servers using reliable, accurate and reproducible measurement methods. The metric applies to general purpose computer servers with up to four processor sockets and with their own dedicated power supply. NOTE 1: The term "socket" also applies to design in which processors are installed without sockets (e.g. soldered products). The metric applies to a computer server model and to a computer server product family, including type and count of CPU, memory, storage, power supplies, cooling (e.g. fans) and any other add-on hardware expected to be present when deployed.