All arithmetical and logical procedures inside a computer/server configuration are tackled by its Central Processing Unit, or CPU. This hardware part is typically called the "brains" of the computer system as well. The pace at which the CPU executes system instructions is commonly referred to as its speed and it's measured in Hertz. The faster the processing unit is, the faster scripts and web applications will be executed, even though the general performance of the latter depends upon other things too - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, and so forth. All newer CPUs have several cores, that work together. Thus, the functionality and the workload that a CPU can handle increase, because each and every core can process different tasks individually and a number of cores can handle a single task which cannot be processed by 1 core.