27" iMac 2017 Drive Setup Options


A few weeks ago we purchased a shiny new 27” iMac for my Wife. Maybe not the best timing given the event later this month, but it’s a beautiful machine and (mostly) a huge upgrade on her old 2011 MacBook Air. I probably should have ordered a BTO unit from Apple, but we were in the store and she was looking at it… and here we are. It’s a damn shame that none of the ‘standard’ models have SSD otherwise I would have just bought that one.

I say mostly because it came with a fusion drive and even coming from a 2011 vintage SSD, it’s a step backwards. To be fair, I didn’t give it a chance to settle it in and get things working on the SSD part of the fusion drive before deciding it just wasn’t fast enough.

For now I have procured a USB3.1 external case and dropped a SATA SSD inside it. I’ve also grabbed a USB-C to micro USB 3.0 adaptor cable (does this support USB 3.1?? who knows). Ideally this would have been a true USB C based case, but they just weren’t available right then and there while I was buying it. I actually grabbed two of these cables and have moved my 2TB USB3.0 mechanical HDD to one of these too which frees up the USB-A connectors and uses the Thunderbolt/USB-C ports which would otherwise be gathering dust.

So now I have 500GB of SSD goodness operating as the boot drive and everything appears to running faster than it was before. Nice. But I can’t help but ponder what could have been or more importantly, what could be.

I don’t believe upgrading the external case to a USB C based one will make any difference and I don’t know that opening this thing up is something I want to do.

An alternative is a NVME based thunderbolt connected drive. Something like the new Samsung X5. It’s not cheap, but it’s probably the easiest and quickest way to get maximum performance without opening the machine up. At around $600 I do wonder if it’s worth it.

Another option (which rather conveniently is $0), it to split the fusion drive and install OSX onto the 32GB internal SSD and then move the home folder to the internal spinning disk for bulk storage. I could even keep the external SSD for storage is I wanted a little more speed for that data. There may be some complexity in ensuring the applications remain on the internal SSD and other files go elsewhere, but it’s all doable. (A bit of a shame it’s only 32GB otherwise this would be much easier). I’m thinking about doing this anyway as the internal drive is just sitting there unused at the moment, I just need some spare time to give it a bash.

Am I likely to notice any difference in doing this or should I just walk away and leave it as is?


Personally, I wouldn’t be paying however much it would be to go from one type of external SSD to the next. It’s much of a muchness at that point. YMMV, but going from a SATAIII internal SSD to an NVME PCIe SSD was not noticeable in my day-to-day.

For simplicity it may be worth installing onto macOS onto the internal SSD, but only because that is effectively free (besides your time, obviously), removes the need to be plugged into an external USB all the time, and frees up an extra USB slot.