I had a few queries recently about slow performance issues in Outlook 2007.
If this sounds like your day-to-day experience and you have a large PST (personal storage) file, then you might benefit from installing the patch at http://support.microsoft.com/kb/933493. This update can help eliminate poor performance while reading, moving, or deleting emails. If this doesn’t help, there are more tips at http://support.microsoft.com/kb/932086.
And while we’re on the subject, a great place to start resolving any issue you encounter with any Microsoft software product is at http://support.microsoft.com. Type your query into the search box (e.g. Outlook 2007 Performance) and you’ll gain instant access to loads of helpful Knowledge Base (KB) and Solution Center articles like these. As long as your hardware meets the minimum system requirements, there’s no need for Outlook to ever run slow. If the advice at the Microsoft Help and Support site doesn’t fix your problems, talk to your helpdesk, email administrator, or someone who can inspect your computer for any possible underlying issues.