All arithmetical and logical procedures in a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware part is occasionally called the "brains" of the computer system as well. The rate at which the CPU runs system instructions is generally referred to as its speed which is measured in Hertz. The swifter the processing unit is, the quicker scripts and web apps will be executed, even though the overall performance of the latter is determined by other things also - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, and many others. All modern CPUs have numerous cores, which work together. Because of this, the functionality and the workload which a CPU can handle increase, since each and every core can process various tasks separately and a number of cores can handle 1 task which can't be processed by a single core.