Outlook Sync CPU

I am trying to keep outlook from using a12% of the CPU when it is minimized. This doesn't always happens. It appears to happen when it is syncing. If I set Outlook to work offline I do not see this issue so I assume it has something to do with sync. I found posts referring to Calendar but I do not have a large Calendar. I do have hundreds of thousands of emails in some folders. My outlook file size is 32G. I've already recreated my profile hoping that would fix it. I would like to be able to keep all of my emails so I can search them.