Oxford Cambridge and RSA
GCSE (9-1) Computer Science
Computer Systems
J277/01
Topic: CPU Performance
Time allowed: 30 minutes
Centre number Candidate number
First name Last name
INSTRUCTIONS INFORMATION
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Section A: Recall & Definitions
1
A computer has a Central Processing Unit (CPU).
Give three characteristics of a CPU that can affect its performance.
[3]
1.
2.
3.
2
The CPU has a clock speed of 3.8 GHz.
Describe what is meant by a clock speed of 3.8 GHz.
[2]
3
Tick one box in each row to show whether each statement is True or False.
[3]
Statement True False
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.
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Section B: Comparative Performance
4
The specification of two CPUs is shown in Fig. 1.
Feature Computer 1 Computer 2
Clock Speed 1 GHz 1.4 GHz
Cache Size 2 MB 2 MB
Number of Cores 4 2
Fig. 1
(a) When running a 3D flight simulator, Computer 1 is likely to run faster than Computer 2.
Using the information in Fig. 1, identify one reason for this.
[1]

(b) Explain why the reason you identified in part (a) improves the performance of the computer.
[2]

(c) Alicia says: "My computer has a quad-core processor (Computer 1), so it will run exactly twice as fast as the dual-core computer (Computer 2)."

Explain why this statement is not always true.
[3]
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Section C: Cache Memory
5
One computer has 64 kilobytes of cache and another has 512 kilobytes of cache.

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.
[6]
END OF QUESTION PAPER