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I have iMac with last 2013 model 21.5 inch screen. Now I want to update my iMac with SSD. So as per your suggestion SATA SSD or M.2 SSD will be better for me?
If your up to it installing the Apple custom blade SSD is the best for performance over swapping out your current HD. Just keep in mind some of the 21.5" models don’t have the SSD hardware (2012 models) so make sure you have this model. Here’s the IFIXIT guide you’ll need to follow: iMac Intel 21.5" EMC 2638 SSD Replacement. Do be careful as you can damage the display quite easily if you don’t use the correct tools and techniques outlined in the guide.
