Outlook Speed Problems Related to "Use Cached Exchange Mode"

[cgfrank]

Good morning

We have a problem with Outlook and "Use Cached Exchange Mode".

If the box is unchecked, Outlook will receive mail quite quickly, as fast as it does on my iPhone using push, but switching between emails or folders is incredibly slow. When I click one mail, and then another, its several seconds to load the 2nd one. Switching folders takes longer.

On the flip side, if I check the "Use Cached Exchange Mode" box, mail takes ages to come (sometime 30 minutes after I get the notification on my phone), but switching from one email to another is almost instant.

How do I configure outlook so it will receive mail fast, and switch between emails quickly too?

Running office 365 on Windows 10.