CompTIA A+® Certification All-In-One For Dummies®, 2nd Edition

2.1. Understanding Processor Terminology

In this section, I cover some basic terms that describe characteristics of different processors, past and present. The exam might not ask for the specific definition of each term, but understanding the terms will help you answer the related questions in this topic area.

2.1.1. Processor speed

Processor speed is how fast a processor executes its instructions or commands. This speed was originally measured in millions of hertz, or megahertz (MHz), per second. A hertz is also known as a clock cycle, and a processor can execute code at every clock cycle. Thus, a processor operating at a measly 1 MHz per second can execute one million tasks every second. Processors today now measure their speed in gigahertz (GHz) per second. A gigahertz is one billion clock cycles per second — so the CPU can execute tasks a billion times per second!

Original CPUs had a speed of 4.77 MHz, and systems at the time of this writing are running over 3.0 GHz. Although processor speed is not the only factor affecting performance, in general, the faster the processor, the faster the system.

2.1.2. Data bus

A city bus is responsible for transferring people from one location to another. In the world of computers, a bus is responsible for delivering data from one location on the PC to another. Data bus is the term used to define the pathway between the processor and memory. Because the processor accesses information from memory so often, an entire bus — the data bus — ...