Thanx, too, to xn (as always!), for the explanation (now fully understood and taken on board!!) that to "get *your* credit", you're actually having to "wait" for the "third" person to complete the same unit on their machine (or, rather, that the pace is determined - in effect - by the "speed" of the slowest machine to return the result). Makes no difference to *you*, though because you're already crunching new units while you're "waiting". And,as you say xn, when 5M people are running BOINC, then the net result will be that it's *your* machine's "speed" that will determine the outcome effectively.