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Upgrading late 2015 27" iMac non-Fusion HDD to SDD

BarkingGhost

macrumors regular
Original poster
Oct 18, 2011
227
3
Atlanta+35 miles
My specific unit here came with an Intel Core i5 running at 3.2 GHz. It came with a mechanical 1TB hard drive. No Fusion drive was configured but I have a question. This product had the option for a Fusion drive setup which means it would have also used an m.2 connector on the logic board. But I do not know if Apple used another logic board for the base model I have that came only with a mechanical drive.

If this base model does have the m.2 connector will it support modern Nvme solid state storage devices by itself? I was curious as I am about to purchase the mounting bracket and install kit to swap out the 1TB HDD for a 1TB SSD. I won't be doing the actual swap--leaving it to professionals.

Anyone upgrade their 27" iMacs of this generation? The 2015 iMac was considered not unendurable beyond the RAM.
 

mindtpi99

macrumors newbie
Nov 28, 2018
13
18
I've done quite a few of these - the connector is keyed differently from the standard m.2 connector. You can buy adapters cheaply on Amazon to use a standard m.2 drive but the few times I've used these I've had a lot of stability issues and have ended up removing them - the money you save isn't worth the hassle in an iMac (maybe worth trying in a system where you don't have to cut off the screen to remove it it fails)

I'd just go to https://fledging.net and get one off them - they plug in straight in and work fine and seem pretty good value but read FAQs carefully regarding EFI and OS version.

If you use a 2.5" SSD to replace the mechanical drive you will need a 3.5" to 2.5" drive plate adapter and an inline thermal sensor to replace the one the mechanical drive has - OWC makes one you can get from MacSales.

If you are going to the trouble of removing the display though, I'd just get the fusion slot SSD and leave the mechanical drive in as a Time Machine backup or extra storage. Once you've got the screen off, it only takes another 15-20 minutes to get the logic board and power supply out anyway and you won't need the drive plate adapter or thermal sensor
 
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rbart

macrumors 6502a
Nov 3, 2013
618
273
France
The M2 "like" connector is installed in your mac.
But you can also swap you HDD with a SATA SSD. You will notice huge performance improvements and it's easier and cheaper than putting an NVME SSD.
In normal usage, it's almost impossible to notice speed difference between SATA and NVME.
 
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BarkingGhost

macrumors regular
Original poster
Oct 18, 2011
227
3
Atlanta+35 miles
Thanks, all, I have ordered the mounting bracket, thermal sensor and Samsung 1TB SSD. So as not to do the work myself, I found a local shop that apparently has been doing this kind of work for a while now. Their price was reasonable considering how much I perceive my time (and frustration) is worth. I'll let you know how things work out. TGIF!
 
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BarkingGhost

macrumors regular
Original poster
Oct 18, 2011
227
3
Atlanta+35 miles
While waiting on the mounting bracket and thermal sensor, is there anything I need to do with the new SSD, which is replacing the HDD, before physically having it installed? It has been a long time since I've been in the Recovery Console (Command+R from the boot gong). Is the Recovery Console embedded in the EFI, or is it installed in a hiddden partition on the physical mechanical drive?

I suppose I could use something like Carbon Copy Cloner, which I've experimented before with to create a bootable SSD used in a docking station and plugged into a 2010 iMac via USB and managed to get it to boot to it. But if the Recovery Console isn't on the HDD then I will not worry about it.

Once in the RC I know how to format the drive, get the WLAN up and then log into the App store to retrieve the operating system. Been there before.
 
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BarkingGhost

macrumors regular
Original poster
Oct 18, 2011
227
3
Atlanta+35 miles
Took about a week and a half to get the parts and another week to get the service done but yesterday I collected the upgraded iMac and used Internet recovery to install El Capitan, which was the version of OS X on the nuit at original purchase (I've since upgraded to Mojave).

In noting the boot up experience, there is still a slight delay which I had hoped to mitigate, and mostly incorrectly blamed the original HDD. But, I am now guessing that any current lag on boot is really just the system performing the equivalent of POST and what not. Still, I am happy with the results thus far and still recommend the mechanical to solid state upgrade. I bet the most modern versions of the iMac, are really fast at booting if they use NvMe.
 
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rbart

macrumors 6502a
Nov 3, 2013
618
273
France
There is also a delay with NVME, it's not related to SSD speed but to some OS operations.
To be sure, clear SMC and NVRAM and check if your SSD is configured as default boot disk in Mac preferences
 
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Fishrrman

macrumors Core
Feb 20, 2009
20,445
7,253
"In noting the boot up experience, there is still a slight delay which I had hoped to mitigate"

Did you open system preferences, then go to "startup disk", and set the SSD to be the new boot drive?
 
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BarkingGhost

macrumors regular
Original poster
Oct 18, 2011
227
3
Atlanta+35 miles
No (Fisherman), but it is the only drive in it. It is fine now but I am having a very odd experience with Mozilla Thunderbird I think I need to post elsewhere.
 
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