The question may be to asses tech-savvy-ness of the candidate (i.e. if he/she knows the SI prefixes, what the range of the modern CPU frequencies is and how do those values reflect on computing performance). There is one kind of programmers that learned their trade just to make a buck and don't care much about their working tools, and there is another kind that finds interest in computers in general. Interviewers may prefer the second kind.