PC Hardware

Lesson Summary: The Centeral Processing Unit

The following points summarize the main elements of this lesson:

  • Replacing a CPU is usually a simple task.
  • It is important to consider the limitations and potential of an upgrade before deciding to replace a CPU.

Tutorial Summary

The following points summarize the key concepts in this tutorial.


  • The CPU (central processing unit)-a microprocessor-is the centerpiece of today's computers.
  • Clock speed is only one determining factor in identifying overall performance of a processor.
  • Processors are generally defined by their speed, the size of the external data bus, and the size of the address bus.
  • The development of the 80286 processor introduced the concepts of real and protected modes and allowed the use of up to 16 MB of memory.
  • The development of the 80386 processor brought about 32-bit processing and allowed up to 4 GB of memory.
  • The 80486 processor is a souped-up version of the 80386 and introduced the use of cache memory.
  • The Pentium chip began a new line of processors and technology, incorporating RISC and true multithreading capabilities in an Intel microprocessor for the first time.
  • The Intel Pentium III further extended PC performance with advanced cache technology and streamlined code handling.
  • Today's standard processor is the Pentium III, with processor speeds of 500 MHz and greater.

Replacing and Upgrading Chips

  • It is important for a computer technician to know the technological advances made by each successive generation of computers.
  • Simply upgrading the CPU can often lengthen the lifespan of a computer.


  1. What is the language of the computer?
  2. What is an external data bus?
  3. Describe an integrated circuit (IC).
  4. Define a clock cycle.
  5. What are the advantages of a Pentium processor over a 486?
  6. What is the difference between "SX" and "DX" in a 386 chip?
  7. Which kind of a computer uses the Motorola 68040 chip?
  8. Define "microprocessor."
  9. In computer code language _____________ means on and ____________ means off.
  10. Define clock speed.
  11. What is the function of the address bus?
  12. Microprocessor chips (CPUs) are manufactured in a variety of sizes and shapes. Name as many different kinds as possible.
  13. Name the basic types of CPU sockets and give a brief description of each.
  14. If a customer brought you an old Pentium 60 and asked you to install a new processor, what would your advice be? Why?
Find the answers here.