Timeout appearing after first save

A freshly installed copy of WP behaves ‘properly’ (with no plugins and default set of options), allowing to add categories and users, and delete comments, until I Edit (the default first) post and press Save and continue after adding a couple of words to it. At this point a weird 72-second (in my case, I believe there can be other numbers in other cases) timeout kicks in, and stays there forever, i.e. even switching between the dashboard and, say, Manage tabs takes 72+ seconds (as displayed in the bottom line of the admin interface). The user side is just as slow.

The following sequence
1. Delete the DB via the mySQL console
2. Create a new DB with the same name
3. Run install.php

remedies the situation until the next attempt at edit/saving. Using a plugin to backup the DB before deleting it and next restoring from backup after step 3 still gives a ‘fast’ version.

Specifically disabling all pingbacks and such does not seem to help.

This all started, I believe, with an upgrade from 2.0.something to 2.1

So here I wonder if something’s wrong with the hosting environment, or it’s a more common WP problem. The option that I’m just dumb is still the most probable one, though