Microsoft speeds up Outlook 2007
Microsoft indicated that the problem stemmed from RSS feeds, email, and calendar files all being stored in the same .PST file which as one might imagine could grow in size rather quickly depending on the user. The problem lies not with the software, but how users are using the software. Jessica Arnold Outlooks Program Manager told ComputerWorld "Outlook wasn't designed to be a file dump, it was meant to be a communications tool...There is that fine line, but we don't necessarily want to optimize the software for people that store their e-mail in the same .PST file for ten years."
Along with the patch Microsoft released an updated set of recommendations to enhance Outlook's performance including moving older emails and files to a separate archived .PST file or splitting a larger .PST file into several smaller ones.