When I first got my hands on a nice new 27″ i5 iMac I was amazed at it’s capabilities, I used it for everything from video editing and web browsing to games and emulation, however as the years passed things seemed slower and slower (or perhaps my expectations grew faster and faster), so I decided to try replacing the optical drive with a nice shiny new SSD. I achieved this by following one of the readily available guides on the internet, purchasing a special optical drive bracket to hold the SSD (the same size as a laptop hard drive, so no doubt the bracket already existed for laptop owners to fit a second hard drive), the results were brilliant – instant speed boost beyond what the iMac was originally capable of in terms of system responsiveness, there was however a drawback… Due to the way the Mac (perhaps it is the hardware, perhaps MacOS, I can’t say) handles hard drives it would always wait for the internal hard drive to wake from sleep before it would do what was asked of it, as it seemed logical to allow the internal hard drive to sleep when not in use; this was also an annoyance when the iMac would wake to check for updates in the middle of the night, as I could hear the hard drive spin up and run (the iMac currently lives in my bedroom).
A few years of this, the trade-off between waiting for the internal hard drive to wake and the speed boost the SSD gave when loading and saving data, and I was happy, until one day the system suffered with a few successive brown-outs that my UPS didn’t manage to protect against! After that moment the SSD started to behave erratically, the system would randomly pause for 30 seconds or more, I was rather concerned that I would lose everything at any moment so I quickly removed the SSD and put it in an external USB case, bracket and all, and ran as many tests as I could, even hooked it up directly to my PC to run low level tests, no faults were found. I subsequently ran the iMac from the external USB SSD until I could find a place for almost 1TB of data that was filling the internal hard drive, so that I could clone the SSD back onto that internal hard drive and go back to how it was originally; that has just been completed (I had to bring a spare 1TB backup drive out of retirement for the purpose).
So far things have been calm, no random system pauses, the system still waits for the internal hard drive to spin up before it will do anything, but at least I don’t have an external SSD taking up space on my desk. Once I am happy that I have everything off that SSD I will blitz it and see what tests I can run on it, I’m convinced there is a hardware fault but it may not be something that software tests can detect, only a burn-in test or regular use will reveal it as being there.
Next time I will fit just an SSD, no regular hard drive, but at the moment the price for large capacity SSDs is ridiculously inflated so it won’t be happening unless I can find a bargain.