---
title: "Performance balance of processor and memory"
subject: "Computer Organization and Architecture"
chapter: 1
key: "semester_5/computer_organization_and_architecture:perf-balance"
source: https://www.bctengineer.com/q/semester_5/computer_organization_and_architecture/perf-balance
site: BCT Engineering
---

# Performance balance of processor and memory

Computer Organization and Architecture · Chapter 1: Introduction

- Asked in: 2072 Chaitra, 2 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/computer_organization_and_architecture/perf-balance
- Whole chapter: https://www.bctengineer.com/md/semester_5/computer_organization_and_architecture/chapter-1

## Question

How can we maintain a performance balance between processor and memory?

## Short answer

Use a small fast cache to reduce average access time, widen the memory data path to fetch more bits per access, and employ interleaved memory banks to overlap accesses. Also use high-bandwidth buses, synchronous DRAM, and more registers to cut memory access frequency.

## Answer

The processor is much faster than main memory, so we balance them by:
1. **Wider memory:** increase the number of bits read per access (a wider data path), so one access supplies more instructions or data.
2. **Cache memory:** put a small, fast cache between processor and memory to cut the average access time.
3. **Interleaved memory:** use several memory banks so accesses overlap.
4. **Faster interconnection:** use a high-bandwidth bus or bus hierarchy.
5. **DRAM improvements:** use synchronous DRAM and similar types for higher data rates.
6. **Reduce memory access frequency:** use more registers and larger caches inside the processor.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How does wider memory help balance?
   A. It slows the processor
   B. It reduces the number of registers
   C. It removes the need for a bus
   D. One access supplies more bits of instructions or data
   Answer: D. More bits per access raises bandwidth. (Key point: Wider memory)

2. What is the purpose of a cache between processor and memory?
   A. To increase memory size
   B. To cut the average access time
   C. To store the OS permanently
   D. To slow the processor
   Answer: B. A small fast memory holds frequently used data. (Key point: Cache)

3. What does interleaved memory do?
   A. Uses one bank for all accesses
   B. Removes the address bus
   C. Doubles the clock speed
   D. Uses several banks so accesses overlap
   Answer: D. Overlapping accesses to different banks raises throughput. (Key point: Interleaving)

## Related in Computer Organization and Architecture

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