CPU clock speed (GHz)

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Quick Questions

Shade in the A or B circle for each question.

1. What does clock speed measure in a CPU?

A How much data the CPU can store

B How many cycles the CPU can run each second

2. A CPU is listed as 3.5 GHz. What does this mean?

A It can run about 3.5 billion cycles per second

B It can run about 3.5 thousand cycles per second

3. Which CPU will usually finish a single task faster, if everything else is similar?

A A 4.2 GHz CPU

B A 2.1 GHz CPU

4. True or false: GHz is the only thing that decides how fast a computer is.

A False. Other things matter too, like the number of cores and the amount of RAM

B True. A higher GHz always makes the whole computer faster

5. Where would you find a CPU's clock speed when comparing laptops?

A On the spec sheet, listed as a number followed by GB

B On the spec sheet, listed as a number followed by GHz

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
13.6 GHz		AGHz means billions of cycles per second, not thousands. 2.5 GHz is 2.5 billion cycles per second.
2Clock speed: 4.5 GHz		BCPU A: 2.0 GHz \| CPU B: 4.0 GHz -> B is usually faster
3A higher GHz usually means a single task finishes faster		C3.0 GHz, 8 cores vs 3.5 GHz, 2 cores
4GHz is not the only measure of speed, because cores also matter		DThe CPU can run 3.6 billion cycles every second
52.5 GHz = 2.5 thousand cycles per second		EA spec sheet line showing how fast the CPU can cycle
6CPU X has the highest GHz, so it is always the fastest CPU		FGHz is not the only measure of speed. Cores and other design features also affect speed, so a higher GHz is only usually faster.

Definitions

Clock speed (GHz)

Fill in the Blanks

Complete each line of code by filling in the missing parts.

CPU: Ryzen 5, Clock speed: 3.6 ___

1 GHz = 1 _______ cycles per second

Clock speed = ______ per second

CPU A: 4.0 GHz CPU B: 2.5 GHz Faster single tasks: CPU _

GHz is not the ____ measure of CPU speed

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A CPU: Core i5

B Clock speed: 3.2 GB

C RAM: 8 GB

Question 2

A 1 GHz = 1 million cycles/sec

B 3 GHz = 3 billion cycles/sec

C 4 GHz = 4 billion cycles/sec

Question 3

A OUTPUT "Compare clock speeds"

B IF 4.0 GHz < 2.0 GHz THEN

C OUTPUT "4.0 GHz is faster"

D ENDIF

Question 4

A Laptop A: 2.4 GHz

B Laptop B: 3.6 GHz

C Higher GHz = more cycles/sec

D Faster clock: Laptop A

Question 5

A CPU X: 4.0 GHz, 2 cores

B CPU Y: 3.5 GHz, 8 cores

C GHz is the only measure

D Cores also affect speed

Answer Key

CPU clock speed (GHz)

Section A: Quick Questions

B — How many cycles the CPU can run each second

A — It can run about 3.5 billion cycles per second

A — A 4.2 GHz CPU

A — False. Other things matter too, like the number of cores and the amount of RAM

B — On the spec sheet, listed as a number followed by GHz

Section B: Match the Pairs

3.6 GHz → The CPU can run 3.6 billion cycles every second

Clock speed: 4.5 GHz → A spec sheet line showing how fast the CPU can cycle

A higher GHz usually means a single task finishes faster → CPU A: 2.0 GHz | CPU B: 4.0 GHz -> B is usually faster

GHz is not the only measure of speed, because cores also matter → 3.0 GHz, 8 cores vs 3.5 GHz, 2 cores

2.5 GHz = 2.5 thousand cycles per second → GHz means billions of cycles per second, not thousands. 2.5 GHz is 2.5 billion cycles per second.

CPU X has the highest GHz, so it is always the fastest CPU → GHz is not the only measure of speed. Cores and other design features also affect speed, so a higher GHz is only usually faster.

Section C: Definitions

Clock speed (GHz) — How many billions of cycles per second a CPU can run. A higher GHz usually means faster single tasks, but it is not the only measure of speed.

Section D: Fill in the Blanks

CPU: Ryzen 5, Clock speed: 3.6 GHz

1 GHz = 1 billion cycles per second

Clock speed = cycles per second

CPU A: 4.0 GHz
CPU B: 2.5 GHz
Faster single tasks: CPU A

GHz is not the only measure of CPU speed

Section E: Spot the Error

B — Clock speed is measured in gigahertz (GHz), not GB. GB (gigabytes) measures storage or memory. It should be 'Clock speed: 3.2 GHz'.

A — One gigahertz is one BILLION cycles per second, not one million. It should be '1 GHz = 1 billion cycles/sec'.

B — 4.0 GHz is higher than 2.0 GHz, so the test must use >. With < the message about 4.0 GHz being faster would never be shown.

D — Laptop B has the higher GHz (3.6 vs 2.4), so it has the faster clock. Line 4 should say 'Faster clock: Laptop B'.

C — GHz is not the only measure of CPU speed. Other things, like the number of cores, matter too. It should say 'GHz is not the only measure'.