I've got an early 2008 iMac that I'd like to keep using until the new Minis come out. It's running a 2.8 GHz Core 2 Duo, and I doubled the RAM to 4GB about a year ago, which reduced the beach ball appearances quite a bit -- until Mavericks. The HD has about 45 GB left. I'm looking for any tips for improving performance with a machine of this vintage. I usually have Outlook, Word, Skype and a browser going simultaneously. Thanks.