Understanding CPU vs GPU

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Curriculum Area

Key Stage 3 – Computing: UK National Curriculum
Relevant areas: “Understand the hardware and software components that make up computer systems, and how they communicate with one another and with other systems.”

This lesson focuses on introducing and understanding the difference between a Central Processing Unit (CPU) and a Graphics Processing Unit (GPU). It's pitched at Year 8 students, providing age-appropriate, relatable examples, and practical tasks.

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Lesson Objectives

By the end of this 45-minute lesson, students will:

1. Explain the role of a CPU in a computer system.
2. Explain the role of a GPU in a computer system.
3. Compare and contrast the purposes of CPU and GPU.
4. Identify real-world examples of how CPUs and GPUs are applied.

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Lesson Outline

Duration: 45 minutes
Class Size: 30 students

1. Starter Activity (5 minutes)

• Objective: Hook students’ interest with a relatable analogy.

• Activity: Start with a question on the board:
  “Imagine a chef in a kitchen making a meal for one customer vs. a pizzeria making 50 pizzas at once. Which is faster? Why?”

  • Use this analogy to introduce the idea that CPUs and GPUs perform tasks differently, with CPUs focusing on sequential tasks and GPUs excelling at multitasking.

• Facilitate a brief class discussion, asking if students have heard of CPUs and GPUs, and where they might encounter them (e.g., gaming consoles, phones, PCs, etc.).

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2. Core Teaching (15 minutes)

Part A: What is the CPU? (7 minutes)

• Present a slide showing the CPU definition:
  The CPU (Central Processing Unit) is the brain of the computer, performing instructions one at a time in sequential order.

• Explain its key characteristics using age-appropriate language:

  • General-purpose processor
  • Handles most computer tasks (e.g., opening programs, browsing the web)
  • Works sequentially like the chef in the starter task

• Demonstrate:

  • Hold up a visual aid, like a simple CPU diagram or an actual spare CPU (if available).
  • Show a slowed-down animation of how the CPU processes tasks (optional idea shared in school assembly style).

Part B: What is the GPU? (8 minutes)

• Present a slide showing the GPU definition:
  The GPU (Graphics Processing Unit) is like a specialist in multitasking, designed for parallel processing and handling a large number of tasks simultaneously.

• Explain its key characteristics:

  • Specialist processor (e.g., creates visuals for video games, powers AI, video editing)
  • Works on a parallel processing model (multiple tasks at the same time)
  • Perfect for graphics-heavy tasks like rendering and gaming

• Show a brief 3D graphics demo: Use pre-downloaded rendered images, videos, or a cardboard visual model to illustrate graphical rendering in motion.

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3. Independent Activity – Sorting Task (10 minutes)

Objective: Assess students’ understanding of the unique roles of CPU and GPU by categorising tasks.

• Hand out a worksheet with a range of example tasks (either printed or as a digital resource):

  • Examples:
    • “Rendering a 3D video game world”
    • “Running calculations for word processing”
    • “AI training and modelling”
    • “Loading an internet browser”
    • “Editing a photo”

• Students work in pairs (2 students per pair) to determine whether each task is CPU-intensive or GPU-intensive.

• Encourage collaboration by walking around the class and asking pairs to explain their thought process.

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4. Class Demonstration and Reflection (10 minutes)

• Use a live demonstration to consolidate learning.

  • On a laptop, show a side-by-side comparison of a CPU-heavy and GPU-heavy task:
    • Example 1: Open a simple program (CPU-focused).
    • Example 2: Play a pre-downloaded short clip demonstrating a 3D-rendered process or simulation (GPU-heavy).

• Reflection activity: Ask students some final questions to ensure understanding:

  • “What would happen if your computer had no GPU?”
  • “Can you think of any tech in everyday life that depends on GPUs?”

• Stretch Task for advanced students: Pose an open-ended question like:

  • “In the future, will GPUs replace CPUs entirely? Why or why not?”

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5. Plenary (5 minutes)

• Quickfire Quiz Game: Organise the students into four groups and ask a series of true/false or multiple-choice questions about the CPU and GPU:

  • Example: “The CPU is best for multitasking. True or False?” (Answer: False)
  • Example: “GPUs are used for AI training. True or False?” (Answer: True)

• Award a point for each correct answer – keep it fun and fast-paced.

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Differentiation

• For EAL learners or students needing additional support:

  • Use visuals, diagrams, and labels to clarify definitions.
  • Allow collaboration during the sorting task.

• For more able students:

  • Offer stretch and challenge options, such as researching further examples of how GPUs are being used in emerging tech (e.g., autonomous vehicles, crypto-mining, etc.).

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Resources

1. PowerPoint Presentation: Definitions and key CPU/GPU concepts
2. Worksheet: Sorting activity (CPU vs GPU tasks)
3. Basic multimedia examples: Pre-downloaded video of 3D rendering and graphics examples (if no internet in class)
4. Spare CPU/GPU (optional) or images of components

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Success Criteria

By the end of the lesson, students should be able to:

• Define what CPUs and GPUs are.
• Articulate their different roles in computers.
• Provide real-world examples of their uses.

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Homework/Extension

Students are tasked to create a mini-poster or infographic at home illustrating one example of how CPUs and GPUs work together in real-world applications. Examples:

• Video gaming
• Animation rendering
• Simulation and forecasting

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Wow your students with relatable examples and interactive activities to make the hardware concepts clear and engaging!