2 votes 2 votes According to my calculation, the time required in write back is 240ns and for write through it should be 1920ns. Is it correct or not? CO and Architecture co-and-architecture cache-memory write-through + – Shubhanshu asked Aug 5, 2017 • retagged Nov 13, 2017 by Arjun Shubhanshu 772 views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments reena_kandari commented Aug 10, 2017 reply Follow Share no actually in write back protocol you also do unnecessary writes because if only one word is changes you have to write the whole block unlike write through. Thats why this question is asked bcz in case of 1 word written, write through will take 30 but write back will take 240ns in case of 2, write through will take 60 but write back will take 240ns in case of 3, write through will take 90 but write back will take 240ns....and so on in case of 8, write through will take 240 but write back will take 240ns, 0 votes 0 votes reena_kandari commented Aug 10, 2017 reply Follow Share no actually in write back protocol you also do unnecessary writes because if only one word is changed you have to write the whole block unlike write through. Thats why this question is asked bcz in case of 1 word written, write through will take 30 but write back will take 240ns in case of 2, write through will take 60 but write back will take 240ns in case of 3, write through will take 90 but write back will take 240ns....and so on in case of 8, write through will take 240 but write back will take 240ns, 0 votes 0 votes Shubhanshu commented Aug 10, 2017 reply Follow Share so , does it means that write through is more efficient than write back??? 0 votes 0 votes Please log in or register to add a comment.