Factor 1: Clock Speed (Measured in GHz)
Part of CPU Performance Factors — GCSE Computer Science
This key facts covers Factor 1: Clock Speed (Measured in GHz) within CPU Performance Factors for GCSE Computer Science. Revise CPU Performance Factors in Systems Architecture for GCSE Computer Science with 15 exam-style questions and 12 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 7 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 7
Practice
15 questions
Recall
12 flashcards
Factor 1: Clock Speed (Measured in GHz)
What It Is:
The CPU operates on a "clock" that ticks at a regular rate. Clock speed measures how many times per second the clock ticks. Each tick is called a cycle.
Measured In:
- Hertz (Hz): 1 cycle per second
- Megahertz (MHz): 1 million cycles per second (1,000,000 Hz)
- Gigahertz (GHz): 1 billion cycles per second (1,000,000,000 Hz)
- Example: A 3.2 GHz CPU ticks 3.2 billion times every second!
How It Affects Performance:
- Higher clock speed = more instructions per second
- The CPU can complete more FDE cycles in the same time
- Example: 4 GHz CPU is roughly twice as fast as 2 GHz CPU (same architecture)
- BUT: Higher speed = more heat and power consumption
Important Limitation:
Not all instructions take the same number of cycles! A simple ADD might take 1 cycle, but a MULTIPLY might take 3-4 cycles. A DIVIDE could take 10+ cycles. So doubling clock speed doesn't always double real-world performance.