Some of the difference can be attributed to how each client connects to the Exchange server. In fact, Microsoft’s own knowledge base says that Mac users may see performance issues if they receive as few as 30 emails per day. Regardless, us Apple lovers pay the price. Or maybe Microsoft has an understandable bias to Windows.
Maybe it’s because the Windows version was built in the same shop as the Exchange service. That’s because, when compared to its Windows counterpart, Outlook for OS X (aka Outlook 2011) is an underperformer.
Update Feb 2015: Are you using Outlook 2015 for OS X? Read the note at the bottom.
