All arithmetical and logical functions in a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware part is occasionally called the "brains" of the computer system also. The pace at which the CPU executes system instructions is generally referred to as its speed and it's measured in Hertz. The speedier the processing unit is, the more quickly scripts and web applications will be executed, although the general performance of the latter depends upon other things too - the read/write speed of the hard drive, the amount of physical memory, the network connection, and many others. All new CPUs have several cores, which work together. As a result, the efficiency and the workload a CPU can manage increase, due to the fact that each and every core can process different tasks individually and numerous cores can handle a single task that can't be processed by 1 core.