All arithmetical and logical procedures within 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 as well. The pace at which the CPU runs system instructions is commonly referred to as its speed which is measured in Hertz. The speedier the processing unit is, the faster scripts and web apps will be executed, even though the performance of the latter is dependent upon other things too - the read/write speed of the hard disk drive, the amount of physical memory, the network connectivity, and many others. All modern CPUs have a number of cores, which work together. Because of this, the effectiveness and the workload a CPU can manage increase, as every single core can process several tasks independently and a number of cores can handle 1 task that cannot be processed by one core.