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Cache Associativity

Associativity

Associativity dictates how a block of memory may be loaded into a cache slot. Cache policies in ascending order of associativity are.

Direct Mapped

One block can only fit in one cache slot

n-way Set Associative

A block can fit in one of n cache slots

Fully Associative

Any block can fit in any cache slot

Effect of Associativity

The more associative a cache is:

  • The more time it takes to search a block within the cache.
  • The less often blocks need to be replaced within the cache.