performance.now() vs Date.now() clock divergence · inter-clock drift
compares performance.now() against Date.now() − performance.timeOrigin — two clocks that share the same epoch but may use different OS sources. drift indicates NTP clock steps, jitter, or browser clamping differences.
drift0.000ms
max |drift|0.000ms
performance.now() − (Date.now() − timeOrigin)ms