You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

2.4 KiB

Systems Architecture Numbers

A systems architecture extension to Peter Norvig's "Latency Numbers" (

TODO: With some scripts to export to other formats like Mnemosyne and Anki.

CPU/Data-transfer (Norvig)

Description Value Unit
Execute typical instruction 1 nanosecond
Fetch from L1 cache 0.5 nanosecond
Branch misprediction 5 nanosecond
Fetch from L2 cache 7 nanosecond
Mutex lock/unlock 25 nanosecond
Fetch from main memeory 100 nanosecond
Send 2 KB over 1 Gbps network 20,000 nanosecond
Read 1 MB sequentially from memory 250,000 nanosecond
Disk seek 8,000,000 nanosecond
Read 1 MB sequentially from disk 20,000,000 nanosecond
Send packet round-trip US-EU 150,000,000 nanosecond


Description Value Unit Date Reference
Twitter mDAU 225,000,000 user monthly visitors 15,000,000 visitor
Github repositories 372,000,000 repository 2023-01
Github users 100,000,000 user 2023-01
Youtube video average viewcount 5,000 view 2015-02


Description Value Unite Date Reference
Nginx TLS terminations 750 second/core 2011