So I've been looking at this for a short while and I'm getting myself horribly confused. I'm hoping someone who understands this better than I might help. I've got the 2013 21.5" iMac. It has a 5400RPM 1TB drive in it (factory standard) I want to put an SSD in. I could replace the current hard drive, but then I lose my storage space. Will this (http://www.crucial.com/uk/store/partspecs.aspx?imodule=CT480M500SSD3) fit in to the PCIe bay, or do I need to source one of the Apple own brand ones - I've seen some sites that suggest that mSATA is the same as the PCIe connection, and others that suggest otherwise. I'm confused as heck. Any help is greatly appreciated.