PC Hardware in a Nutshell, 3rd Edition

Processor Design

A processor executes programs—including the operating system itself and user applications—all of which perform useful work. From the processor’s point of view, a program is simply a group of low-level instructions that the processor executes more or less in sequence as it receives them. How efficiently and effectively the processor executes instructions is determined by its internal design, also called its architecture. The CPU architecture, in conjunction with CPU speed, determines how fast the CPU executes instructions of various types. The external design of the processor, specifically its external interfaces, determines how fast it communicates information back and forth with external cache, main memory, the chipset, and other system components.