If this were a real OS :) I'd say you need to use whatever your particular flavour of iostat is to get statistics on things such as paging and how much time you're spending in disk wait (and for Solaris recommend a copy of the Porsche book by Cockcroft). I'm guessing there's probably some analogue for Windows (other than the Task Manager) that should be able to collect similar statistics.

And "Perl", not "PERL".