Consider a single-level cache with an access time of 1.8ns, a line size of 16 bytes, and a hit ratio of 0.85. Main memory uses a block transfer capability that has a first word (4 bytes) access time of 40 ns and an access time of 5 ns for each word thereafter.
Suppose that increasing the line size to 64 bytes increases the hit ratio to 0.95. What is the average memory access time?
- 9.55ns
- 8.55ns
- 7.55ns
- 10.75ns
I know the answer is 7.55ns
while calculating the Main Memory Access time = 40ns(first 4 bytes) + 75 (remaining 60 bytes)
How it get 75ns accesstime ? After 4 words each words is accessed at 5ns Access time.?