I am so tired of Mail.app constantly running at 100-200% CPU load on Yosemite! It drains my battery, makes the fans run loud, being hot, and it's just a pain... So what are any worthy alternatives for Mail.app? I love the GUI and search. But having only 2 hours of battery time when having Mail open completely ruins it. I have looked on the new Outlook, and it actually looks pretty neat. Anyone who uses that? The only thing I do, is writing mails, sending some attachments once in a while. I have the following mail accounts in Mail.app: - 2 IMAP accounts - 2 Exchange accounts - 1 Gmail account So it should be able to work with all of those (preferably with a unified inbox).