If cache access time is 100ns, main memory access time is 1000ns and the hit raio is 0.9. Find the average access time and also define hit ratio.

RGPV 2020

Solution:

Given,

Cache access time = 100ns

Memory access time = 1000ns

Hit ratio = 0.9

Average access time = Hit ratio x Cache access time + (1 – Hit ratio) x Main memory access time

Using above formula:

Average access time = 0.9 x 100ns + (1 – 0.9) x 1000ns = 190ns