I need some help and guidance... I have been using my 2009 iMac 24" for a few years and have an iPhoto Library of about 44,000 photos (140GB). Recently I removed my SuperDrive and replaced it with a Crucial M4 256GB SSD that I "fused" to my 2TB WD Black HD - installed Mountain Lion and then restored from Time Machine - all went smoothly. The one app I was looking to see performance gains from was iPhoto. However, I am not seeing the performance gains on iPhoto I was expecting - in particular closing the app. So I rebuilt the iPhoto Database - still the same... Downloaded iPhoto Library Manager and made a "rebuilt" copy of my iPhoto Library and still the same - most of the time. So I got to thinking - what the heck is causing this slowdown and CPU spike on closing? Then I discovered when I turn off Photo Stream all together iPhoto closes just about instantly and no CPU spike. No matter what boxes I have checked on for Photo Stream, if any are checked, iPhoto takes up to 30 seconds to close. My internet connection is about 30mbps down and 5mpbs up. I would like to have photo stream enabled so my iPhone photos get imported into iPhoto automatically and I can create shared photo streams. Does anyone else see this with iPhoto and Photo Stream enabled?