Exam-style question
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A processor has a 16-bit address bus and an 8-bit data bus. Explain how increasing the address bus to 20 bits and the data bus to 16 bits could affect the computer's performance or capability. Do not assume that either change increases clock speed.
Model answer
What a good answer should say
- Increasing the address bus from 16 bits to 20 bits increases the number of different addresses that can be represented, so the processor can address a larger range of memory locations.
- Increasing the data bus from 8 bits to 16 bits allows twice as many bits of data to be transferred in one bus operation, assuming the other components can support this width.
- This may reduce the number of transfers needed for data that is wider than 8 bits and can improve data transfer performance.
- Neither change directly increases the clock speed, so they do not necessarily make every instruction execute faster.
Explanation
Why this works
The address bus affects the range of memory locations that can be addressed, whereas the data bus affects the amount of data transferred at one time. Keeping these roles separate is essential.
The answer also avoids incorrectly claiming that bus width directly changes clock speed.
Common mistake
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