Scaled Latency Number

Event                                        Latency            Scaled
1 CPU cycle                                  0.3    ns          1       s
Level 1 cache access                         0.9    ns          3       s 
Level 2 cache access                         2.8    ns          9       s
Level 3 cache access                         12.9   ns          43      s
Main memory access (DRAM, from CPU)          120    ns          6       min
Solid-state disk I/O (flash memory)          50-150 us          2-6     days
Rotational disk I/O                          1-10   ms          1-12    months
Internet: San Francisco to New York          40     ms          4       years
Internet: San Francisco to United Kingdom    81     ms          8       years
Internet: San Francisco to Australia         183    ms          19      years
TCP packet retransmit                        1-3    s           105-317 years
OS virtualization system reboot              4      s           423     years
SCSI command time-out                        30     s           3       millennia
Hardware (HW) virtualization system reboot   40     s           4       millennia
Physical system reboot                       5      m           32      millennia

Reference: System Performance Enterprise and Clouds by Brendan Gregg.