All arithmetical and logical operations in a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware part is typically called the "brains" of the personal computer also. The rate at which the CPU carries out system instructions is commonly referred to as its speed which is measured in Hertz. The swifter the processing unit is, the faster scripts and web applications will be executed, even though the efficiency of the latter depends on other things also - 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. Subsequently, the efficiency and the workload that a CPU can manage increase, because each and every core can process different tasks separately and a number of cores can handle a single task which can't be processed by 1 core.