All arithmetical and logical functions inside a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware component is usually called the "brains" of the computer system too. The pace at which the CPU runs system instructions is typically referred to as its speed and it's measured in Hertz. The swifter the processing unit is, the quicker scripts and web programs shall be executed, though the general performance of the latter is dependent upon other things as well - the read/write speed of the hard disk, the amount of physical memory, the network connectivity, and so on. All current CPUs have several cores, which work together. Thus, the overall performance and the workload a CPU can handle increase, since each and every core can process a number of tasks separately and a number of cores can handle one task which can't be processed by a single core.