I’ve been beta-testing this update for a little while and it seems to make quite a difference to the performance of Outlook 2007 (especially at startup) when you have large PST files, or a large offline cache of a mailbox. The Outlook team released it live, yesterday.
http://support.microsoft.com/kb/933493
I’d highly recommend giving it a go – it’s one of those updates where you might not really notice much positive improvement after you’ve installed it, but you do notice that there are less of the times where you notice there’s a performance problem 🙂
