CPU

CPU

1. Purpose and Function

   • The Processor will carry out this cycle over and over, 1 million times per second
     • Fetch- From Main Memory
     • Decode- This happens in the CPU, by something called the Program Counter
     • Execute- This can be a number of things: Loading Data from memory, Storing Data in Memory orPerforming a calculation
   • Because it carries out 1 million calculations per second it gets very hot
     • Heat Sink draws air out of the CPU, with a fan then blowing it out of the computer
   • Registers are small storage locations in the CPU

2. Clock Speeds

   • The Clock Speeds of a computer are measured in Hertz (Hz)
   • There can be some Major Disadvantages to Overclocking a CPU
     • The CPU produces more heat- If the CPU produces too much heat it can damage the processor
     • The lifetime of the CPU is reduced- Will need replacing when it stops working
   • Clock Chip- A device inside the computer that controls the timing of the signals by sending out a pulse

3. Contains the Control Unit, ALU and Cache Memory

   • ALU- Arithmetic Logic Unit, performs logical and arithmetic functions

4. Cache Memory

   • It is an area of memory that can be accessed quickly by the CPU.
   • It is used to store regularly used items so they can be loaded faster.
   • Your web browsers save web pages here when you open them for the first time.
   • Why is Cache Memory preferable to RAM?
     • It is much faster than RAM for the CPU to access

5. CPU Cores

   • Processors on a chip are called Cores, if there are 2 of these on a single processor, its called a dual processor etc.
   • One processor can have four cores is and are called quad processors, with one of the cores usually disabled if one corrupts
   • Multi-core processors usually work on seperate operations, but they CAN work together to get the job done quicker
   • Having more cores in a processor can make a computer run faster. But having two cores will never be as fast as having one core running at twice the speed