All arithmetical and logical operations within a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware element is usually called the "brains" of the computer system also. The rate at which the CPU carries out system instructions is usually referred to as its speed and it's measured in Hertz. The faster the processing unit is, the more quickly scripts and web applications will be executed, even though the performance of the latter depends upon other things also - the read/write speed of the hard drive, the amount of physical memory, the network connectivity, and so forth. All newer CPUs have multiple cores, which work together. For that reason, the functionality and the workload which a CPU can handle increase, as every single core can process different tasks individually and a number of cores can handle one task which can't be processed by one core.