Chosen Solution
Hey gang- My late 2013 iMac 27 has a 3TB Fusion Drive. When installing a new SSD to replace the mechanical drive, is the original SSD portion (in my case 128gb) no longer used? If used, does it still function as a single fused drive with the new SSD?
The blade SSD is the cache drive for the fusion drive set. I pull it out as it can get in the way and you can’t use it with your replacement SSD drive. It’s too small of a drive to be useful. I often replace it with a much larger blade SSD and make it the boot drive, leaving the HDD alone. You will need this iMac Intel 21.5" and 27" (Late 2012-Late 2015) SSD Temperature Sensor when you pull the HDD as Apple leverages the HDD’s diagnostic sensor to manage the systems thermals. Once the drive is gone you loose a needed sensor, as such your systems SMC services will go into CPU Safe Mode as it freaks out not getting its input. When in Safe Mode the CPU’s clocking is lowered and the fan is rev’ed up.
