Is it just an extra preset like High Performance and Power Saver or does it actually add certain tweaks not available though Advanced Power Settings?
It's just a few settings that are changed, actually i can only find the "turn off harddisk after...." is set to never instead of the default 20min.
AFAIK, it enables some new features in the new very high power PC's. The differences without and with Ultimate Performance could be seen in the use of some test apps before and after the change.
MS didn't hide 'stuff like this', the users of the software from MS just didn't read on MS Websites 'everything' about the related software. Every (or at least MOST) feature, aspects etc. of any MS Software could be found via the MS Websites! It's just terrible how much time the user has to spend to find that info. What I'm missing all the years, is a really advanced Search System at MS Websites to find what a user is looking for!