That is VERY slow. Try disabling MS Security Essentials. Here's a thread in which it caused a problem. MS Security Essentials. The symptoms aren't the same but it's a good starting point.

I just had a client solve their performance issue with a different solution. They had been complaining about slow speed for a couple of years so I suggested IT move Adagio another server. Load times were cut in half. Of course that assumes an environment with 2 or more servers!