Mail > Preferences > General
and then set "Check for new messages:" to 1 minute
Apple Mail, with the @mac, @me or @cloud, usually takes longer than mail from a POP account. POP accounts only check what's new and send it while the Exchange type mail does a lot more before the mail arrives.
You can see that activity if you click the Window menu item in the menu bar and select Activity.
P
I am gradually getting used to my Mac after being a PC user for 30 years I guess. Something I find very frustrating is that when I start my MacBook up, which is wonderfully quick, the mail client doesn't seem to download new messages in the mail client for quite a long period. I've tried "Mailbox>Get All New Mail" and "Mailbox>Get New Mail", "Mailbox>Synchronise All Accounts" another options, but none of them seem to trigger the send/receive process. All of a sudden the mail client seems to do it, but in its own sweet time. Is there an option I need to set/unset or is there something else I need to do to kick the mail exchange into life?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic