Systems architecture
OCR GCSE Computer Science revision on Systems architecture. Aligned to the OCR GCSE Computer Science J277 specification. This bank has 8 practice questions on this topic.
Sample questions (3 of 8)
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Question 1
What does CPU stand for?
- A) Central Processing Unit
- B) Computer Processing Utility
- C) Core Programming Unit
- D) Central Programming Utility
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Answer: Central Processing Unit
The CPU processes instructions using the Fetch-Decode-Execute cycle. Made up of the Control Unit (CU), the Arithmetic Logic Unit (ALU), and registers. Modern CPUs have multiple cores so they can run multiple FDE cycles in parallel.
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Question 2
In the Fetch-Decode-Execute cycle, the FETCH stage retrieves the next instruction from...
- A) The hard drive
- B) Cache
- C) RAM (main memory)
- D) The CPU's registers
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Answer: RAM (main memory)
Fetch — instruction copied from RAM to the CPU using the address held in the Program Counter (PC). Decode — Control Unit works out what the instruction means. Execute — the ALU performs the operation. Registers store temporary values during this cycle. Cache speeds it up by holding frequently-used data closer to the CPU.
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Question 3
Increasing clock speed (e.g. from 3 GHz to 4 GHz) generally...
- A) Reduces processing speed
- B) Increases processing speed and heat output
- C) Has no effect on performance
- D) Increases storage capacity
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Answer: Increases processing speed and heat output
Clock speed = the number of FDE cycles per second. Higher = faster, but also draws more power and generates more heat — so processors are often clocked lower than they physically could run, to stay within thermal limits. Cache size, number of cores, and architecture also matter.
Want to test yourself on the remaining cards for this topic?
5 more questions on Systems architecture — plus mistakes tracking and spaced repetition across the whole Computer Science spec.