All arithmetical and logical functions in a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware part is sometimes called the "brains" of the computer system too. The rate at which the CPU completes system instructions is typically referred to as its speed and it is measured in Hertz. The swifter the processing unit is, the faster scripts and web applications shall be executed, though the performance of the latter depends on other things also - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, etc. All current CPUs have numerous cores, which work together. Because of this, the overall performance and the workload a CPU can take care of increase, since every core can process various tasks individually and numerous cores can handle one task which cannot be processed by one core.