[eru]

And most of the time that's the right trade-off.

Not all the time, though. Eg consider a video game: the image frames have to be pumped out on a tight time budget every couple of milliseconds, but the logic to decide whether you have finished your quest can afford to run for a few seconds in the background.

Even though the latter is much simpler and could probably be coded up to run on even the Timex m851 in fractions of a second.