Chosen Solution
Hello everyone I have an iMac 27” 5K Late 2014 4.0Ghz i7 with an installed Apple blade drive. I removed it and installed a Crucial BX500 960Gb SSD. BUT, i didn’t install the OWC thermal sensor adaptor for this. For my surprise the fan seems to work fine, no over-speeding. Is this normal? can it be OWC have listed this model by mistake, to use the thermal sensor?
Apple is very secretive on what they change either within the hardware as well as the systems firmware (EFI) between the models and overtime. So far I too have discovered the Late 2014/Mid 2015 27” iMac’s seem not to need the in-line sensor when an SSD is swapped out for the HDD when you have a blade SSD present (was previously a Fusion Drive config). I’m not sure if this is intended or not. Apples unique thermal sensor config’ed 3.5” HDD’s are still present in the latest models so I would be careful here. It’s likely the system firmware is thinking this is a Blade SSD only system and does not ‘See’ the HDD (SSD) within the systems firmware as Apple would assume it was one of their custom drives not an off the shelf drive in your case a SSD. So… What to do?? Clearly a SSD does not run as hot as a HDD so you might be able to get away without the in-line sensor (low drive I/O). If you are using a 4 TB or larger SSD I would use the in-line sensor as these larger SSD’s can get quite warm! (high drive I/O) If you are swapping out the HDD for a larger off the shelf HDD I would stick with the in-line sensor to be safe from cooking my system. Note: This is only when there is a Apple blade SSD present! If not, you do need the in-line sensor! It would be nice for Apple to properly document things than having us bouncing around in the dark!
