Fetch-Decode-Execute Cycle: GCSE Computer Science Definition

Robert Hampton

Written by: Robert Hampton

Reviewed by: James Woodhouse

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What is the fetch-decode-execute cycle?

In GCSE Computer Science, the fetch-decode-execute (FDE) cycle, also known as the fetch-execute cycle, is defined as the cycle that the central processing unit (CPU) runs through billions of times per second to make a computer work.

Diagram of a CPU with arrows illustrating the fetch-decode-execute cycle, showing how processors handle instructions.
Illustration of the fetch-decode-execute cycle

The four main steps of the fetch-decode-execute cycle are:

  • An instruction or data is fetched from memory

  • The instruction is decoded 

  • The instruction is executed

  • The cycle repeats billions of times per second

Fetch-Decode-Execute Cycle Revision Resources to Ace Your Exams

Explore the fetch-decode-execute cycle in more detail to understand the origin of instructions and explore the various types of instructions the CPU is likely to process during execution in our revision note pages here:

The purpose of the CPU (OCR GCSE Computer Science)
Fetch-execute cycle (AQA GCSE Computer Science)
CPU components & their function (Edexcel GCSE Computer Science)

Challenge yourself with our expertly created topic questions and reinforce your learning with our interactive flashcards

GCSE Computer Science Revision Resources

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Robert Hampton

Author: Robert Hampton

Expertise: Computer Science Content Creator

Rob has over 16 years' experience teaching Computer Science and ICT at KS3 & GCSE levels. Rob has demonstrated strong leadership as Head of Department since 2012 and previously supported teacher development as a Specialist Leader of Education, empowering departments to excel in Computer Science. Beyond his tech expertise, Robert embraces the virtual world as an avid gamer, conquering digital battlefields when he's not coding.

James Woodhouse

Author: James Woodhouse

Expertise: Computer Science

James graduated from the University of Sunderland with a degree in ICT and Computing education. He has over 14 years of experience both teaching and leading in Computer Science, specialising in teaching GCSE and A-level. James has held various leadership roles, including Head of Computer Science and coordinator positions for Key Stage 3 and Key Stage 4. James has a keen interest in networking security and technologies aimed at preventing security breaches.

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