As a completely new user of Premier Elements 8 (running on a AMD phenom 3 core, 4g Ram, 500G Sata HD, Win Xp prof) I brought into Organise in the PE8 workspace clips imported in through Windows Movie Maker from my old DV video camera. I wanted to dectect the scene boundaries so I ran Auto-Analyse from the PE8 workspace. This took upto 4 hrs to analyse a 1hr clip which puzzled me as Movie maker only took about 20mins to detect the scenes on a much slower and lower spec laptop.
If you just want to Scene Detect don'r run Auto-Analyze from Premier workspace instead start with your first clip via the Organiser. Reason - In the PE8 workspace "Edit" "preferences" Auto-Analyze does not appear so it will run with the defaults which is all tag options selected e.g "focus" "face recognition".
Instead go into Organise from the front page launcher, in "Edit" "preferences" Autoanalyse does appear with all the tag options selected as default If you deselect all options and then run Autoanalyse on the video clip only scene detection runs on the video (the 1 hour clip was analysed with just the scene boundaries in less than 15mins!) The change from the default seems to apply when you run from the PE8 workspace after this so subsequent scene detection on other clips runs quickly.
Old hands may know this trick but so far I had not picked anything up from the web based docs and information - so this is for novices such as myself. There may be other ways of scene detection but in my limited experience have not come across any yet.