Maybe more experienced people can see the effects of various architecture decisions, but it would be great if the diagram explained how adding a node in the dia

Maybe more experienced people can see the effects of various architecture decisions, but it would be great if the diagram explained how adding a node in the diagram adds or subtracts to user wait times, or speed or something. Can experienced users tell: oh yeah, that extra caching layer will let them handle a million more users at peak time keeping lags below 2 secs?