I have the 27" 2012 iMac with 768GB SSD. I've read that the SSD is a blade, meaning I should have a free SATA port in there somewhere. Shouldn't I be able to add a standard 2.5 SSD drive? I'm thinking a 512GB Samsung 840 Pro. I seriously doubt I would do it myself. I've read you can take it to an authorized Apple repair store to get aftermarket drives installed without voiding the warranty. (Excluding the addition.) I do not want an external drive. I bought an all-in-one, I'd rather like to keep it that way.