All arithmetical and logical procedures inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware part is typically called the "brains" of the personal computer too. The rate at which the CPU runs system instructions is commonly referred to as its speed and it's measured in Hertz. The swifter the processing unit is, the faster scripts and web applications shall be executed, though the overall performance of the latter depends upon other things as well - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, and so forth. All modern CPUs have a number of cores, that work together. As a result, the functionality and the workload a CPU can manage increase, due to the fact that each and every core can process different tasks separately and several cores can handle one task which can't be processed by a single core.