I/O Latency in Relative Terms

If Rotational disk I/O were one to twelve months, a CPU Cycle would be one second.

Event	Latency	Scaled
1 CPU Cycle	0.3 ns	1 second
Level 1 cache access	0.9 ns	3 second
Level 2 cache access	2.8 ns	9 seconds
Level 3 Cache access	12.9 ns	43 seconds
Main memory access (DRAM, from CPU)	120 ns	6  min
Solid-state disk I/O (flash memory)	50-150 µs	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 UK	81 ms	8 years
Internet: San Francisco to Australia	183 ms	19 years
TCP packet retransmit	1-3 s	105-317 years