CPU Performance

This lesson covers the three main factors that affect CPU performance: clock speed, number of cores, and cache size. These are commonly examined in AQA and OCR GCSE Computer Science.

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Why Does CPU Performance Matter?

The speed at which a CPU can process instructions determines how quickly programs run, how smoothly games play, and how fast files are processed. Three key hardware features influence this performance:

1. Clock speed
2. Number of cores
3. Cache size

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1. Clock Speed

What Is Clock Speed?

The clock speed (also called clock rate or clock frequency) measures how many instructions a CPU can process per second. It is measured in hertz (Hz).

• 1 MHz (megahertz) = 1 million cycles per second
• 1 GHz (gigahertz) = 1 billion cycles per second

A typical modern desktop CPU runs at between 3 GHz and 5 GHz — that means it can perform 3 to 5 billion cycles per second.

How Does It Affect Performance?