High Quality Content by WIKIPEDIA articles! In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are (typically) addressed by mechanisms other than main memory and can be accessed more quickly. Almost all computers, load-store architecture or not, load data from a larger memory into registers where it is used for arithmetic, manipulated, or tested, by some machine instruction. Manipulated data is then often stored back in main memory, either by the same instruction or a subsequent one. Modern processors use either static RAM or dynamic RAM as main memory, the latter often being implicitly accessed via one or more cache-levels. A common property of computer programs is locality of reference: the same values are often accessed repeatedly and frequently used values held in registers improves performance. This is what makes fast registers (and caches) meaningful.