All arithmetical and logical functions inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware component is occasionally called the "brains" of the PC as well. The rate at which the CPU completes system instructions is commonly referred to as its speed which is measured in Hertz. The speedier the processing unit is, the quicker scripts and web programs shall be executed, even though the overall performance of the latter is dependent upon other things as well - the read/write speed of the hard disk drive, the amount of physical memory, the network connectivity, etc. All current CPUs have several cores, that work together. Therefore, the efficiency and the workload a CPU can manage increase, because every core can process several tasks separately and several cores can handle 1 task which cannot be processed by one core.