I just want to point out that all late 2013 iMacs have the slot for the Blade SSD. iFixit if you could please correct your literature it may encourage people to install the blade SSD instead of only the 2.5" SATA. to be sure I pulled apart 3 21.15" iMacs today which DID NOT ship with blade SSD drives or Fusion drives. I'd be happy to share any model info etc. So everyone feel free to upgrade to the Blade SSD as it is superior to the 2.5"