All arithmetical and logical procedures inside a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware element is sometimes called the "brains" of the personal computer as well. The rate at which the CPU carries out system instructions is usually referred to as its speed and it's measured in Hertz. The speedier the processing unit is, the speedier scripts and web applications will be executed, although the efficiency of the latter depends upon other things also - the read/write speed of the hard disk, the amount of physical memory, the network connection, and many others. All modern CPUs have multiple cores, which work together. Thus, the efficiency and the workload which a CPU can manage increase, as every single core can process a number of tasks individually and numerous cores can handle one task that cannot be processed by a single core.