That's true, but he only asked "which one is a more processing power" (not the best grammar, but a direct quote, nonetheless).
That's an easy answer.
IF he wanted to use one of the 2 in a multi proc stystem, then obviously, the Xeon is a no-brainer because there isn't any other choice (Xeon's only, I mean).
Edit: Although I would strongly advise against using an older (slow, at that) Xeon for that purpose.