All arithmetical and logical operations inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware element is typically called the "brains" of the personal computer too. The pace at which the CPU runs system instructions is typically referred to as its speed and it's measured in Hertz. The swifter the processing unit is, the more quickly scripts and web programs will be executed, though the overall performance of the latter is dependent upon other things too - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, and many others. All current CPUs have multiple cores, which work together. Thus, the overall performance and the workload that a CPU can tackle increase, because every core can process different tasks separately and numerous cores can handle a single task which cannot be processed by a single core.