Mensagem original de: Dan ,
A Fusion Drive is made up of two devices a traditional hard drive and a SSD drive which is fused into a single volume. Please review this [http://www.macworld.co.uk/news/mac/ssd-vs-hard-drives-which-best-storage-have-mac-3463640/|SSD vs hard drives: which is the best storage to have in a Mac]. So the next question is do you want to break the fusion drive set alone here or are you thinking of replacing the HD with a second SSD? While you can replace the HD with a second SSD you will loose your warranty coverage so make sure you want to risk this with such a new system. If you haven't bought your system yet or can return it think about going with a low end Mac Pro system instead. While it will be a bit more it will allow you more options. OK, you still want to move forward here. First you'll need to break the Fusion Drive set. Follow this: [http://www.macworld.com/article/2015664/storage-flash/how-to-split-up-a-fusion-drive.html|How to split up a Fusion Drive]. The next step here is opening your system. You need to be very careful here as you can very easily damage the display. The newer 'Thin Series' iMac's use tape to hold the display on make sure you follow this IFIXIT guide: [guide|27886|iMac Intel 21.5" EMC 2805 Hard Drive Replacement] while this guide is for the older system it is exactly the same for your system. Make sure you get the correct tools and follow the guide to the letter so you don't damage the display.