All arithmetical and logical functions 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 too. The pace at which the CPU carries out system instructions is generally referred to as its speed and it's measured in Hertz. The quicker the processing unit is, the more quickly scripts and web apps shall be executed, although the general performance of the latter is dependent upon other things too - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, and so on. All modern CPUs have numerous cores, that work together. For that reason, the efficiency and the workload a CPU can handle increase, since each and every core can process several tasks separately and several cores can handle one task which can't be processed by 1 core.