it's a Core 2 Duo

Okay. That explains it. Two cores versus one.

I couldn't figure out what you were doing with dividing the time by $N-1,

Actually, I'm dividing by $N and then subtracting one.

The total time will be N*1 + N*(time of interest); so dividing by N gives 1 + (time of interest); -1 leaves (time of interest).

The idea of the sleep was to simulate doing something else in the interim--there being no point in multitasking it, if all your going to do is wait for the results.

Not a great benchmark I admit, but it did get me a set of numbers to consider, rather than just anecdotal "forks are faster than threads on *nix". Thanks :)

ps. Suggesting that win32 is "DOS" is very tacky. 'sides, even if it was DOS, it'd still be a decade newer than that Multics derivitive that you seem to like :)