Macs are picky about RAM and RAM from local sources will NOT work in a Mac.īefore embarking on a major OS upgrade, it would be wise, advisable and very prudent if you have a good,working backup of your current system to an external connected and Mac formatted Flash drive OR externally connected USB, Thunderbolt or FireWire 800, Mac formatted hard drive. Newer versions of OS X need all the RAM they can get.Ĭorrect, compatible and reliable Mac RAM can ONLY be purchased from online RAM sources Crucial memory or OWC ( ).ĭO NOT PURCHASE RAM FROM LOCAL COMPUTER OR ELECTRONICS STORES! At, least 4 GBs of RAM and I strongly recommend you max your 2009 iMac's RAM to 8 GBs.
