Updating from Fedora Core 4 to FC5 test 2 takes 210 (3.5 hours). This is excessive. By comparison, a new installation of FC5 test 2 takes 50 minutes on the same system.
I'm not exactly sure how to address this bug. Most likely the lengthy time is due to using yum within the installer, and perhaps you had an excessive amount of packages on your FC4 install. This takes time to chew through. We are working on speeding up yum within anaconda, but there is only so much one can do. I'm going to close this as a cantfix at this time.