Wordpress non registered comments slow to post / tracing php

Wordpress non registered comments slow to post / tracing php

I bought a cheap vps and installed apache 2.2, MySQL and wordpress.
Overall it runs pretty well with decent page load times. If I am logged in
as admin I can make post comments and they save very quickly however as a
non registered / anonymous user when I try to save a comment it takes 45 -
60 seconds to save.
I have tried using fast cgi and mod_php but the results are similar.
This is an out of the box install with no plugins or non stock themes
enabled.
Is there a way to trace the calls made during the post process? I have
tried setting wp debug but that doesn't provide much logging.