All arithmetical and logical procedures within a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware part is usually called the "brains" of the computer also. The pace at which the CPU executes system instructions is generally referred to as its speed which is measured in Hertz. The swifter the processing unit is, the faster scripts and web applications shall be executed, though the performance of the latter depends upon other things too - the read/write speed of the hard drive, the amount of physical memory, the network connection, etc. All newer CPUs have multiple cores, that work together. As a result, the efficiency and the workload which a CPU can tackle increase, since every single core can process several tasks independently and a number of cores can handle 1 task that cannot be processed by 1 core.