=== 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
  Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
  Read 4K randomly from SSD*              150,000   ns    0.15 ms
  Read 1 MB sequentially from memory      250,000   ns    0.25 ms
  Round trip within same datacenter       500,000   ns    0.5  ms
  Read 1 MB sequentially from SSD*      1,000,000   ns    1    ms  4X memory
  Disk seek                            10,000,000   ns   10    ms  20x datacenter roundtrip
  Read 1 MB sequentially from disk     20,000,000   ns   20    ms  80x memory, 20X SSD
  Send packet CA->Netherlands->CA     150,000,000   ns  150    ms

==== Notes ====
  1 ns = 10-9 seconds
  1 ms = 10-3 seconds
  * Assuming ~1GB/sec SSD

=== Credit ===
  By Jeff Dean:               http://research.google.com/people/jeff/
  Originally by Peter Norvig: http://norvig.com/21-days.html#answers

=== Contributions ===
  Some updates from:                      https://gist.github.com/2843375
  Great 'humanized' comparison version:   https://gist.github.com/2843375
  Visual comparison chart:                http://i.imgur.com/k0t1e.png
  Nice animated presentation of the data: http://prezi.com/pdkvgys-r0y6/latency-numbers-for-programmers-web-development/