"Numbers Everyone Should Know" from Jeff Dean. Slides #1, Slides #2 (which are different)
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns
Mutex lock/unlock 100 ns
Main memory reference 100 ns
Compress 1K bytes with Zippy 10,000 ns 0.01 ms
Send 1K bytes over 1 Gbps network 10,000 ns 0.01 ms
Read 1 MB sequentially from memory 250,000 ns 0.25 ms
Round trip within same datacenter 500,000 ns 0.5 ms
Disk seek 10,000,000 ns 10 ms
Read 1 MB sequentially from network 10,000,000 ns 10 ms
Read 1 MB sequentially from disk 30,000,000 ns 30 ms
Send packet CA->Netherlands->CA 150,000,000 ns 150 ms

Where