All arithmetical and logical operations inside a computer/server configuration are tackled by its Central Processing Unit, or CPU. This hardware element is usually called the "brains" of the computer system too. The pace at which the CPU runs system instructions is typically referred to as its speed and it is measured in Hertz. The speedier the processing unit is, the faster scripts and web programs will be executed, although the general performance of the latter is determined by other things also - the read/write speed of the hard disk, the amount of physical memory, the network connection, etc. All modern CPUs have several cores, that work together. Subsequently, the overall performance and the workload which a CPU can manage increase, since every single core can process several tasks individually and numerous cores can handle 1 task that can't be processed by one core.