All arithmetical and logical procedures in a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware part is sometimes called the "brains" of the PC also. The rate at which the CPU carries out system instructions is typically referred to as its speed and it is measured in Hertz. The quicker the processing unit is, the speedier scripts and web applications shall be executed, though the 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, etc. All newer CPUs have a number of cores, that work together. Subsequently, the effectiveness and the workload which a CPU can handle increase, as each and every core can process several tasks separately and several cores can handle 1 task which cannot be processed by a single core.