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I have a iMac 27" 5K (late 2015) 1tb fusion. (1tb hdd + 24gb ssd) So I want to replace 1TB HD to Crucial MX300 SSD 750GB. Will I need the “OWC In-line Digital Thermal Sensor for Hard Drive Upgrade for 27” iMacs 2012 and Later"? https://eshop.macsales.com/item/OWC/DIDI… As I understand it, that is for Hard Drive upgrades, not needed for SSD. right ?
Yes, you still need the OWC in-line thermal sensor! It’s not an issue of which kind of drive you put in. While a SSD runs a lot cooler than an HD, the problem is the systems thermal management system depends on the input of the sensor to know whats happening. If you fail to replace it the system goes into fail safe mode running the fans at high speed and lowers the CPU’s clocking.