Since instal Maverick, my iMac had become my-application memory fault. After careful verification that the product was consistent my 2009 iMac, the upgrade from 2G to 8G transformed and now works fine (fast, multi-apps). The product is packed, the illustrations to install the bars are clear (identify how those are mounted in place). The install goes in minutes being careful (small Phillips screwdriver needed, pull hard the old strips). PS: Maverick (? Free) is huge and cost me a memory upgrade and lose sync Calendar and Contacts.