Performance should be slightly better for the Northwood if the POS software can take advantage of HT, but you should also take into consideration that it runs much cooler than the Presscott. I may be wrong, but a POS probably doesn't require a very powerful processor.
Sorry, it's a regular computer; it's just a piece-o-shix. (actually it's fine; it's just old, circa 2004)
Does that change anything?