Cache memory

1.2.1 Primary Storage (memory)

Primary Storage (memory) — Note 6 of 6

What you need to know

Cache memory is a very small but extremely fast type of primary storage located inside or very close to the CPU. It stores frequently used data and instructions so that the CPU can access them more quickly than from RAM.

What to know

Cache is faster than RAM but much smaller in size.
It stores copies of frequently accessed data and instructions from RAM.
By keeping frequently used data close to the CPU, cache reduces the time taken to access data.
This improves overall system performance and speeds up processing.

Key terms

Cache Memory: A small, very fast memory located inside or close to the CPU that stores frequently used data and instructions.

Exam technique

Mistake:Saying cache replaces RAM. It does NOT replace RAM — it works alongside RAM.
Mistake:Saying cache stores permanent data. It only stores temporary copies of frequently used data.
Tip:If asked why cache improves performance, mention that it reduces the time needed for the CPU to fetch frequently used data.
Tip:The hierarchy in terms of speed (fastest to slowest) is: Cache → RAM → Secondary Storage.

Example:In a gaming PC, instructions for repeatedly used game calculations may be stored in cache to speed up processing.

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