You can check which information is send over the internet when it does nothing. You can check that with a program like ethereal.
With the information you receive, you can see if it is waiting for information, or getting a lot of information. You can also see what happended after 10 minutes, when the page suddenly does come through.
Althought the output of this kind of programs are mostly technical, maybe you can find some clues about this problem.
WARNING: The output almost always contains private information, so do not simple post the output.