All arithmetical and logical operations inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware element is occasionally called the "brains" of the PC as well. The pace at which the CPU carries out system instructions is usually referred to as its speed and it is measured in Hertz. The speedier the processing unit is, the speedier scripts and web apps will be executed, though the efficiency of the latter is determined by other things too - the read/write speed of the hard drive, the amount of physical memory, the network connection, and so forth. All new CPUs have multiple cores, which work together. Because of this, the functionality and the workload which a CPU can take care of increase, as each core can process various tasks individually and several cores can handle a single task which can't be processed by 1 core.