Upgrading 2015 27" iMac 5K with new NVMe stick and new 2,5" SATA SSD - but without NVMe enclosure?

[Yiveymacnod]

Hi! I've posted this question in the "A list of successful iMac 27" (2012-2019) SSD upgrades" thread but maybe it isn't the right thread for this support. If not, I'm sorry for double posting.

I'm upgrading my base late-2015 27" 5K iMac that today only have a 1TB HDD. I'm putting in a 1TB WD Black SN750 NVMe M.2 and a 1 TB WD Blue SATA SSD.

Since I haven’t got an NVMe-USB enclosure I’m thinking if it’s possible to do the reinstall a bit unconventional...

Here’s my plan:
1. Since I already have a SATA-USB3 adapter, use that to format the new 2,5” SATA SSD.
2. Clone the existing HDD to the 2,5” SATA SSD with SuperDuper or CCC.
3. Tear open the iMac.
4. Install the untouched (not formatted) NVMe stick and the newly cloned to 2,5” SATA SSD.
5. Boot from the new 2,5” SATA SSD.
6. Format the NVMe stick in Disk Utility. Possible?
7. Clone the 2,5” SATA SSD to the NVMe stick. Possible?
8. Restart and boot from the NVMe stick.
9. If everything works, format the 2,5” SATA SSD and wipe it clean.
10. Install some kind of TRIM utility or run it in Terminal for the 2,5” SATA SSD. (Done this before in an older MBP, but can't remember how I did it?! 😝)
11. Set NVMe as startup disk.

What do you think of this plan?

I know it’s possible to buy a NVMe to USB adapter for €35-40 but I’m a student now so I’m trying to save some. 😇

Of course I both have a Time Machine backup and won’t touch the original 3,5” HDD until everything is done.

 

[tah18]

So did your strategy above work?

I have read through the other post you mention - very helpful but gets a little long to tedious to sift through.

 

[Yiveymacnod]

So did your strategy above work?

I have read through the other post you mention - very helpful but gets a little long to tedious to sift through.

Yes it worked perfectly. Here's how I did:

Another success! 👍

Device: iMac 27” 5K - Late 2015 - 17.1 - (3.2Ghz i5-6500, HDD only)
Location: Sweden, Europe
Blade upgrade: none -> 1TB OWC Aura Pro X2 PCIe NVMe SSD
HDD to SSD upgrade: 1TB original Seagate SATA HDD -> 1TB 2.5” WD Blue SATA SSD
CPU upgrade: no upgrade
Speed test NVMe SSD: ~3000 MB/s read, ~2550 MB/s write
Speed test SATA SSD: ~510 MB/s read, ~400 MB/s write
OS before: Catalina 10.15.7
OS after: Big Sur 11.2.3
Adapter: No adapter needed with the OWC blade
Heatsink for blade: Glotrends NVMe heatsink
Mounting bracket 3.5” to 2.5”: Corsair Dual Solid-State Drive Mounting Bracket
Adhesive strips for the screen: iFixit
Temperature sensor: not required
Boot-ROM before upgrade: 428.x.x.x (never got stuck on 170.x.x.x most likely due to the iMac never being shipped with a blade SSD)
Boot-ROM after upgrade: 429.80.1.0.0
TRIM: Enabled by default for the OWC (didn't expect that..), but not for the SATA SSD (expected)


Issues during install:
1. Since the iMac wasn’t shipped with a blade from factory it had no screw to secure the blade. Naively I thought I would have one in my rather big stash of different bits and bobs - but no sir. Luckily I was able to source one similar locally, after calling around to at least 4 different shops that handle electronics. For anyone wondering, the original Apple Part Number is 923-0336. It’s a M2,5x3,0 (mm) with a big flat head.
2. I'd forgot that I needed a long T10 screwdriver to reach the one screw in the middle of the logic board. Had to go get one from work.
3. The 2.5” SSD had to be mounted in the top slot on the dual bracket due to cable management. Managed to route the SATA cable through the back of the adapter to line everything up.


Issues after installation:
None, sleep and everything works.


Thoughts and questions:
- I had originally planned on installing a 1TB WD Black SN750 with the Sintech ST-NGFF2013C, but I got a really really good deal on an OWC Aura Pro X2 so I changed my mind in the last minute. I’ll use the WD blade in an enclosure with my iPad Pro instead, or throw it in my unRAID server.

- Since the heatsink was bought with intent to use with the adapter (needed to be thin), perhaps it could’ve been larger. But I don’t think it’ll be an issue. Didn’t use the metal springs to attach the heatsink to the blade, only used the silicone bands. Felt like I would risk shorting the blade if I used the metal ones, time will tell if the silicone will hold up.
View attachment 1755715

- The iMac 17.1 isn’t (!) one of the supported Macs for the OWC Aura Pro X2 according to OWC but from what I can understand that’s probably due to an EFI issue with these models. See this thread for more info:
https://forums.macrumors.com/thread...te-2015-efi-firmware-update-failures.2228324/ Since I have no issues with EFI I thought I’d give it a chance. So far no problem and I don’t expect any either. My theory is that OWC and others don’t want to risk problems with 17.1 and therefore skipped support for it. I’ve got the WD blade and the adapter if issues occur.

- I've found different sources saying different things about TRIM being enabled by default for NVMe blades.
Some say it's only automatically enabled for Apples own blades, some say its enabled for all NVMe by default, some say all 3rd party SSDs (NVMe and SATA) never have TRIM enabled by default..
Well, my OWC was enabled. Thats good. The SATA SSD wasn't, as expected, so I guess I still will have to run the trimforce command. Shouldn't affect the blade in any negative way, right?


How I did the cloning and install of macOS, for anyone unsure:
First, always take a backup!
I cloned the HDD to the 2.5” WD Blue SATA SSD with Carbon Copy Cloner using a old external enclosure. Did the teardown and install of everything and put the screen back on without the adhesive strips.
Booted into the SATA drive first to see if everything was working and that the OWC blade was recognized.
Shut everything down and booted into Internet recovery mode (option+cmd+r).
The OWC blade was pre-formatted with HFS+ so I had to erase it in Disk Utility and change it to APFS instead.
Returned to Internet Recovery menu and chose to install a fresh Big Sur. After some steps I could choose between the internal drives and chose the OWC blade. Everything installed fine.
During the setup process for Big Sur I could choose to start fresh or recover data from a Time Machine backup, another Mac or a startup disk. Here I chose the 2.5” SATA SSD and transferred everything to the new install.
I could’ve used CCC again when booted into the 2.5” SATA SSD and cloned everything to the OWC blade, but since I was on Catalina to start with I thought I try this way first. If the Big Sur install wasn’t successful for some reason I could just wipe the OWC blade again and go the CCC route.
I’ll run it like this, keeping the 2.5” SATA SSD clone for a while, to test out Big Sur.


Now I’ll just have to figure out if it’s better/faster to run 32GB 1866MHz RAM, or 64GB 1600MHz RAM. I’ve got both... 🤷‍♂️😅 Any ideas?

 

[tah18]

Thanks for your detailed description. 👍 I believe I had read your post previously in the other thread, but good to see it again. Going to try a similar approach. Unfortunately, I use SuperDuper, which presently is no longer able to make a bootable copy in Big Sur (may be fixed soon..?). Nevertheless, I appreciate all the other info.

 

[Yiveymacnod]

Thanks for your detailed description. 👍 I believe I had read your post previously in the other thread, but good to see it again. Going to try a similar approach. Unfortunately, I use SuperDuper, which presently is no longer able to make a bootable copy in Big Sur (may be fixed soon..?). Nevertheless, I appreciate all the other info.

Carbon Copy Cloner has a free trial so no reason not to use it imo. =)