On my Windows box, I've been using Outlook 2013 to access five IMAP accounts, some of which have thousands of emails in them. Over time, Outlook has begun to perform so poorly that there is now a delay of over ten seconds from the time that I click on an email to the time that it's displayed. This is on a machine with 16GB RAM, an i7, an SSD-- Outlook is the only program that exhibits performance problems.
Can anyone recommend a Windows email app that performs well with large amounts of email, and includes good search functionality as well? Thanks very much!