Technically true, if your program only processes a large chunk of stuff once and never has to wait for network activity, disk access, user input or some other kind of external event. NOPs aren't what the parent spoke of, however. These days, a program typically uses a blocking call or voluntarily yields execution when there's nothing for it to react to, so in the absence of active processes the OS can tell the processor to halt (possibly slowing down or turning off parts of itself until an interrupt comes by and wakes it up).
QBasic was written to be run as the sole program on an architecture which didn't have the benefit of such features, so it uses a different mechanism, which is a bad fit to modern power saving schemes.
Hope that helps.