Latency numbers every programmer should know

latency.txt

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                    4x mutex op, 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy        3,000 ns
Send 2K bytes over 1 Gbps network   20,000 ns
Read 1 MB sequentially from memory  250,000 ns
Round trip within same datacenter   500,000 ns
Disk seek                           10,000,000 ns             20x datacenter roundtrip
Read 1 MB sequentially from disk    20,000,000 ns             80x reading in seq from memory 
Send packet CA->Netherlands->CA     150,000,000 ns

By Jeff Dean (http://research.google.com/people/jeff/):