Clock drift alludes to few related phenomena where a clock does not run at exactly the same rate as a reference clock. After some time the clock “drifts apart” or gradually desynchronizes from the other clock. All clocks are liable to drift, causing eventual divergence except if resynchronized. Specifically, the drift of crystal-based clocks utilized in PCs needed some synchronization component for any rapid communication. Computer clock drift can be used to make random number generators.