All arithmetical and logical operations inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware component is typically called the "brains" of the computer also. The pace at which the CPU runs system instructions is generally referred to as its speed and it's measured in Hertz. The faster the processing unit is, the faster scripts and web apps shall be executed, though the overall performance of the latter is dependent upon other things also - the read/write speed of the hard disk drive, the amount of physical memory, the network connectivity, and so on. All modern CPUs have a number of cores, that work together. Because of this, the overall performance and the workload which a CPU can take care of increase, since each core can process different tasks separately and several cores can handle one task which can't be processed by a single core.