gcsecomputerscience.co.uk
Multi-Core XP 0 / 20
Power Rank Core 1
1 [3 Marks]
Give three characteristics of a CPU that can affect its performance.
✅ Mark Scheme
  • Clock Speed
  • Cache Size
  • Number of Cores
⚠️ Examiner's Trap Do not accept "RAM" or "SSD". These are not part of the CPU.
Score yourself (Max 3):
2 [2 Marks]
The CPU has a clock speed of 3.8 GHz.
Describe what is meant by a clock speed of 3.8 GHz.
💡Hint: Mention "cycles" and how many per "second".
✅ Mark Scheme
  • The number of FDE cycles run per second. (1)
  • 3.8 billion cycles per second. (1)
⚠️ Common Mistake Do not just say "Speed of the computer".
Score yourself (Max 2):
3 [3 Marks]
Tick one box in each row to show whether each statement is True or False.
Statement Selection
If a CPU has many cores, this always slows down the computer.
Cache memory is slower to access than RAM.
A dual-core processor has two processing units.
✅ Mark Scheme
  1. False
  2. False (Cache is faster)
  3. True
Score yourself (1 mark per correct row):
4 [6 Marks Total]

Computer 1: 1 GHz, 4 Cores
Computer 2: 1.4 GHz, 2 Cores

(a) When running a 3D flight simulator, Computer 1 (4 Cores) is likely to run faster. Identify one reason why. [1]
(b) Explain why your reason improves performance. [2]
(c) "Computer 1 (Quad Core) will run exactly twice as fast as Computer 2 (Dual Core)."
Explain why this statement is not always true. [3]
💡Hint 4c: Does all software use 4 cores? What about if one task depends on another?
✅ Mark Scheme

(a) Reason: Computer 1 has more cores.

(b) Explanation:

  • Allows parallel processing.
  • More tasks can be processed simultaneously.

(c) Why not twice as fast?

  • Software might not be designed to use multiple cores.
  • Some tasks are sequential (cannot be split).
  • Other components (RAM, Clock Speed) affect speed.
Score yourself (Max 6):
5 [6 Marks]
Explain how the cache size can affect the performance of the CPU.
In your answer, refer to what cache stores and how it compares to RAM.
💡Hint: Is Cache faster or slower than RAM? What does it store?
✅ Mark Scheme
Indicative Content:
  • Cache stores frequently / recently used instructions or data.
  • Cache is faster to access than RAM.
  • More cache means more data is closer to the CPU.
  • This reduces the need to fetch from slower RAM.
  • CPU spends less time waiting, improving efficiency.
Score yourself (Max 6):