Dr. Dean from Google reveals the length of typical computer operations in 2010 [1]. Some numbers are outdated as computers become faster and more powerful. However, those numbers should still be able to give us an idea of the fastness and slowness of different computer operations.

Operation name Time

L1 cache reference 0.5 ns

Branch mispredict 5 ns

L2 cache reference 7 ns

Mutex lock/unlock 100 ns

Main memory reference 100 ns

Compress 1K bytes with Zippy 10,000 ns = 10 µs

Send 2K bytes over 1 Gbps network 20,000 ns = 20 µs

Read 1 MB sequentially from memory 250,000 ns = 250 µs

Round trip within the same datacenter 500,000 ns = 500 µs

Disk seek 10,000,000 ns = 10 ms

Read 1 MB sequentially from the network 10,000,000 ns = 10 ms

Read 1 MB sequentially from disk 30,000,000 ns = 30 ms

Send packet CA (California) ->Netherlands->CA 150,000,000 ns = 150 ms