Clock speed or more cores: which helps which task

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Quick Questions

Shade in the A or B circle for each question.

1. Your old single-task game runs on only one core and feels slow. Which upgrade helps most?

A A CPU with a higher clock speed (GHz)

B A CPU with more cores

2. You have a browser, music, a chat app and a document all open at once. What helps most?

A More cores, so programs can run side by side

B Only a higher clock speed

3. Which statement is true about clock speed?

A A higher GHz adds extra cores to the CPU

B A higher GHz makes a core finish its steps faster

4. A video editor exports a video. The software splits the work into parts. Which CPU suits it better?

A 2 cores, because video export only uses one core

B 8 cores, because the parts can run at the same time

5. A quad-core CPU is always exactly four times faster than a single-core CPU. True or false?

A False

B True

Match the Pairs

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

Left column		Right column
1cpu.clock = 4.5 GHz		AMany programs open together is a many-tasks job, so more cores would help more than clock speed alone
2cpu.cores = 8		Bexport_video(cores = 8)
3Exporting a video can be split into parts, so extra cores can each work on a chunk at the same time		CThis assumes a perfect 4x speed-up, but parts of a task cannot be split, so the real gain is smaller
4A quad-core CPU is not always 4x faster, because some of the task cannot be split across cores		DA higher clock speed makes a single task run faster, because each core finishes its steps more quickly
5Many programs open at once is slow, so buy a higher GHz single core only		EMore cores let many programs, or one job split into parts, run at the same time
6quad_core_time = single_core_time / 4		Fspeedup < 4 * single_core

Definitions

clock speed vs cores

Fill in the Blanks

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

oneTask = TRUE IF oneTask THEN raise _____ speed ENDIF

openApps = 8 IF openApps > 4 THEN add _____ ENDIF

exportParts = 4 IF exportParts _ 1 THEN PRINT "use many cores"

speedup = 3.2 IF speedup _ 4 THEN PRINT "not 4x faster"

speed = 3.6 ___ IF speed > 3 THEN PRINT "fast one task"

Spot the Error

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

Question 1

A jobs = 1

B if jobs > 1:

C print("Higher GHz helps")

Question 2

A jobs = 6

B if jobs > 1:

C print("Fewer cores help")

Question 3

A cores = 4

B parts = 8

C t1 = 40 # mins on 1 core

D ideal = t1 * cores

Question 4

A unit = "GB"

B speed = 3.6

C print(speed, unit)

Question 5

A cores = 4

B real_speedup = 2.8

C print(real_speedup == cores)

Answer Key

Clock speed or more cores: which helps which task

Section A: Quick Questions

A — A CPU with a higher clock speed (GHz)

A — More cores, so programs can run side by side

B — A higher GHz makes a core finish its steps faster

B — 8 cores, because the parts can run at the same time

A — False

Section B: Match the Pairs

cpu.clock = 4.5 GHz → A higher clock speed makes a single task run faster, because each core finishes its steps more quickly

cpu.cores = 8 → More cores let many programs, or one job split into parts, run at the same time

Exporting a video can be split into parts, so extra cores can each work on a chunk at the same time → export_video(cores = 8)

A quad-core CPU is not always 4x faster, because some of the task cannot be split across cores → speedup < 4 * single_core

Many programs open at once is slow, so buy a higher GHz single core only → Many programs open together is a many-tasks job, so more cores would help more than clock speed alone

quad_core_time = single_core_time / 4 → This assumes a perfect 4x speed-up, but parts of a task cannot be split, so the real gain is smaller

Section C: Definitions

clock speed vs cores — Higher clock speed (GHz) speeds up one task at a time; more cores help when many tasks, or a task split into parts, run together. Quad-core is not always 4x faster.

Section D: Fill in the Blanks

oneTask = TRUE
IF oneTask THEN raise clock speed
ENDIF

openApps = 8
IF openApps > 4 THEN add cores
ENDIF

exportParts = 4
IF exportParts > 1 THEN
  PRINT "use many cores"

speedup = 3.2
IF speedup < 4 THEN
  PRINT "not 4x faster"

speed = 3.6 GHz
IF speed > 3 THEN
  PRINT "fast one task"

Section E: Spot the Error

B — One job means a single task running at a time, so the test should be jobs == 1. Higher clock speed speeds up one task. jobs > 1 would describe many tasks.

C — With many tasks running together, extra cores let them run side by side. The message should say more cores help, not fewer.

D — An ideal video export split across 4 cores takes the one-core time divided by the number of cores. Multiplying would make the export take longer, which is wrong.

A — CPU clock speed is measured in gigahertz (GHz). GB means gigabytes, which measures storage or memory size.

C — A quad-core is not always 4x faster, because some work cannot be split up. The real speedup is usually less than the number of cores, so it should use <.