08-17-2018 09:41 PM
08-22-2018 12:25 AM
Is the firmware on the SSD up to date?
How about the SMC & BootROM firmware on the MBPro? You can check here to see if it is up to date. FYI, the Apple firmware updaters will only work on the original version of OSX which shipped with the laptop. It will not run using a later major version so you would need to install the original OS to an external drive to update the firmware.
You could try reseating the hard drive cable on the Logic Board. The cable could also be bad. Some other posts on these forums mention issues with certain SSDs and NVidia chipsets.
I also know another Mac centric site recommends using only a 3G SSD (SATA II locked speeds of 3Gb/s) on some older Apple systems as the Apple SATA controllers cannot always negotiate the speed automatically. Apple only designed the system to work with their own original components.