Reminiscent of the old joke where the physicist says "let's assume the horse is a sphere." But while a sphere might be a good model for a horse, it's definitely

Reminiscent of the old joke where the physicist says "let's assume the horse is a sphere." But while a sphere might be a good model for a horse, it's definitely not a good model for how actual computers currently work. In other words, the "actual" in the title should be replaced with "theoretical", with a footnote saying "under a theory that is worse than the one you are already using." Of course, nobody would read it then.