Latency Comparison Numbers - Every web developer should know

Latency Comparison Numbers
L1 cache reference	0.5 ns
Branch mispredict	5   ns
L2 cache reference	7   ns                      14x L1 cache
Mutex lock/unlock	25   ns
Main memory reference	100   ns     20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy	3,000   ns        3 us
Send 1K bytes over 1 Gbps network	10,000   ns       10 us
Read 4K randomly from SSD*	150,000   ns      150 us          ~1GB/sec SSD
Read 1 MB sequentially from memory	250,000   ns      250 us
Round trip within same datacenter	500,000   ns      500 us
Read 1 MB sequentially from SSD*	1,000,000   ns    1,000 us    1 ms  ~1GB/sec SSD, 4X memory
Disk seek	10,000,000   ns   10,000 us   10 ms  20x datacenter roundtrip
Read 1 MB sequentially from disk	20,000,000   ns   20,000 us   20 ms  80x memory, 20X SSD
Send packet CA->Netherlands->CA	150,000,000   ns  150,000 us  150 ms

Notes ----- 1 ns = 10^-9 seconds 1 us = 10^-6 seconds = 1,000 ns 1 ms = 10^-3 seconds = 1,000 us = 1,000,000 ns
Credit ------ By Jeff Dean               Originally by Peter Norvig