CPU Components & Their Function (OCR GCSE Computer Science)

What are the components of the CPU?

• The CPU is made up of 4 key components
  • Arithmetic Logic Unit (ALU)
  • Control Unit (CU)
  • Cache
  • Registers
• Each of the components sits within the CPU

What is the function of each component?

Arithmetic logic unit (ALU)

•  Performs arithmetic operations
• Performs logical decisions
  
  • IF X > 5 THEN
          DO ……….

Control unit (CU)

• Coordinates how data moves around the CPU by sending a signal to control the movement of the data 
• Decodes the instructions fetched from memory

Cache

• Very small, very fast memory located in the CPU which is used to provide quick access to frequently used instructions and data
• The more cache there is, the more data can be stored, which speeds up the performance of the CPU
• It prevents the CPU from having to repeatedly fetch frequently used instructions from RAM

Registers

• Extremely small, extremely fast memory located in the CPU
• Each register has its very own specific purpose
• More details about the individual registers can be found here