All arithmetical and logical procedures inside a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware component is sometimes called the "brains" of the personal computer as well. The rate at which the CPU executes system instructions is generally referred to as its speed and it is measured in Hertz. The faster the processing unit is, the faster scripts and web programs will be executed, even though the efficiency of the latter is dependent upon other things too - the read/write speed of the hard disk, the amount of physical memory, the network connection, and many others. All new CPUs have multiple cores, which work together. Thus, the effectiveness and the workload a CPU can handle increase, since every core can process a number of tasks independently and numerous cores can handle one task that can't be processed by 1 core.