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Will this SSD (Samsung 860 Evo 250GB) be work in iMac 21.5’ 2011 (MC309)? Thanks.
Yes, it should work for you. However you will have the racing fan issue so I suggest buying the SSD upgrade kit linked below (it has the temperature sensor you need to stop the racing fans along with a 3.5” to 2.5” converter).
iMac Intel 21.5" and 27" (Mid 2011) SSD Upgrade Kit
