django extreme slowness
Then I thought it might be a DNS
  issue, but the site loads instantly
  when served with Apache2.

How are you serving your Django site? I presume you're running mod_python on Apache2? 
You may want to start by running an Apache2 locally on you computer (use MAMP or WAMP and install mod_python there) and seeing if it's still slow. Then you can tell whether it's a django/python issue or an Apache/mod_python issue
I have a slowness problem with Django and I can't find the source .. I'm not sure what I'm doing wrong, but at least twice while working on projects Django became really slow.
Requests takes age to complete (~15 seconds) and Validating model when starting the development server is also very slow (12+ seconds on a quad core..)
I've tried many solution found on the net for similar problem, but they don't seem related to me.
The problem doesn't seem to come from Django's development server since the request are also very slow on the production server with apache and mod_python.
Then I thought it might be a DNS issue, but the site loads instantly when served with Apache2.
I tried to strace the development server, but I didn't find anything interesting.
Even commenting all the apps (except django apps) didn't change anything.. models still take age to validate.
I really don't know where I should be looking now ..
Anybody has an idea ?