All arithmetical and logical functions in a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware component is usually called the "brains" of the computer also. The pace at which the CPU carries out system instructions is typically referred to as its speed and it's measured in Hertz. The swifter the processing unit is, the faster scripts and web programs will be executed, even though the general performance of the latter is dependent upon other things also - the read/write speed of the hard disk, the amount of physical memory, the network connection, and so on. All modern CPUs have a number of cores, that work together. Because of this, the effectiveness and the workload which a CPU can manage increase, since each core can process various tasks individually and several cores can handle one task that can't be processed by a single core.