Symptom: If you're seeing random, periodic extremely slow page refreshes on your iMIS app server (full or public view, either one), check the first section of this Howto for the ASP.Net "idle worker process timeout" setting.
The issue is that by default, IIS kills the ASP.Net worker process after 20 minutes of inactivity, causing the next page access to restart the appdomain (leading to that annoying "first hit" slowdown as all the business objects are loaded, iBO initialized, etc).