An External SSD Gave My iMac a New Lease on Life

Beyond my expertise! The 1 to 2 TB leap is really huge in price, for sure. Anandtech is a great site about technical details, and they may have an actual explanation of how to evaluate features in NVMe. They have written a lot about NVMe.

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Hmm, I found this updated model by Sandisk which doubles the previous modelā€™s speed to 2000 MB/s. Still not as fast as your OWC at 2800. But at $339, itā€™s a lot less than $500. Just placed an order.

https://www.amazon.com/SanDisk-2TB-Extreme-Portable-SDSSDE81-2T00-G25/dp/B08GV4YYV7/ref=sr_1_4?dchild=1&keywords=SDSSDE61-2T00-G25&qid=1621883854&sr=8-4

There are far less expensive solutions using one of the best SSD circuitries consumers can currently buy. The key is to stop trying to buy expensive all-in-one solutions from companies that have grown accustomed to Mac users being gullible simpletons that you can easily rip off.

Bottom line, get a NVMe Samsung blade (970 EVO Plus) and a solid TB3 enclosure along with it. Assemble in 30 seconds. Done.

Youā€™re right. I saw some pricy enclosures that steered me away from that idea. Plus that model was back ordered a bunch of places. But I did some more homework and got what is hopefully a good setup based on in stock products.

That drive is $309 here

SAMSUNG 970 EVO Plus SSD 2TB - M.2 NVMe Interface Internal Solid State Drive with V-NAND Technology (MZ-V7S2T0B/AM) https://www.amazon.com/dp/B07MFZXR1B/ref=cm_sw_r_cp_api_glt_fabc_XQ4XCGZ3W3G9YWHM8C4H

This sabrent was a lot cheaper but the Samsung name is more familiar to me:

Sabrent Rocket Q 2TB NVMe PCIe M.2 2280 Internal SSD High Performance Solid State Drive R/W 3200/2900MB/s (SB-RKTQ-2TB) Amazon.com

I did choose to get the pricey enclosure for thunderbolt 3 even though the usb-c one would have been close to accommodating the bandwidth for a lot less money.

So @glennf !

I came back here to follow your instructions.

Why did you complicate moving your startup disk to an external SSD with also upgrading to Big Sur? Is there anything necessary about that to make this work?

In any case, my boot volume is already Big Sur. But Iā€™m just trying to understand. I know Apple does some weird things in OS upgrades regarding what is allowed to boot externally (SSD, APFSā€¦)

I was only running Mojave because I had two ā€œmission-criticalā€ apps. Once I upgraded to the SSD, everything ran ridiculously faster, including Parallels. At that point, I decided to take the plunge to upgrade to Big Sur, as I could run Mojave in a VM.

Aha, okay, got it :-)

  • I set System Preferences > Startup Disk to boot from the cloned SSD.

This step didnā€™t work for me. The newly-copied-to SSD did not present as an option as a Startup Disk. Tried it 2-3 times, including at least once using the ā€œLegacy Bootable Backup Assistantā€¦ā€ feature of CCC.

However, I just went ahead and Restarted and used Option, and was able to select the SSD at boot time.

I am looking at at getting an SSD to continue the life of my 2017 iMac. I currently have a 1TB hard drive. It looks like I can get a 1 TB SSD for under $200. What is the minimum ā€œMaximum Data Transfer Rateā€ I should get? Is there anything else I should watch for when buying the drive?

I wouldnā€™t worry about performance all that much. Any modern SSD is going to be so much faster than your hard drive that youā€™ll be happy with it.

I would instead look for what reviewers have to say about reliability and longevity.

Thanks, David. Iā€™ll look for reviews

And donā€™t overpay. $200 for no-frills 1TB is preposterous.

This is a very decent drive for $110.

Thanks for reminding me that the @steveeight is (I think) looking to replace the internal SATA hard drive. I think it is safe to assume that all but the worst SSDs will perform well enough to max-out a SATA interface (at 6 Gbit/s).

Higher performance SSDs (e.g. those with NVMe interfaces), when used with a 2017 iMac, only make sense if mounted in an external Thunderbolt enclosure (which can go up to a theoretical 40 Gbit/s) Its USB 3 ports only go up to 5 Gbit and are therefore slower than the internal SATA interface.

Update: I double-checked and found that the 2017 iMac also has an NVMe slot. If youā€™re going to open the case to access/remove the hard drive, then you might want to look at installing a 1TB NVMe drive, which will outperform any SATA device. But that may cost more and the performance of a SATA SSD will still be much faster than the old hard drive.

Getting to the NVMe slot will, I think, require disassembling the entire iMac and removing the motherboard, which would likely make the installation bill higher. As long as that hard drive is still working, Iā€™d go with an external SSD and use the 1 TB drive as a backup. I would also be careful to make sure the NVMe SSD was compatible with the Macā€™s slot before buying.

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Clarification: I am looking for an EXTERNAL ssd. That being said, I was looking at portable ssd that were USB-C. It appears that I should have been looking at Thunderbolt. Since then I looked at Thunderbolt enclosures and a ssd to put in the enclosure. I was looking at the following enclosure and ssd:
https://www.bhphotovideo.com/c/product/1577064-REG/owc_owctb3envxp00_envoy_express_thunderbolt_3.html?sts=pi&pim=Y
https://www.bhphotovideo.com/c/product/1576657-REG/crucial_ct1000p2ssd8_p2_1tb_nvme_pcie.html

Any thoughts are helpful. Thanks

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I have a iMac 27ā€ 5K Retina Fusion drive (late 2014). Iā€™ve maxed the memory but itā€™s been running slower and slower over the years but it was still tolerable until I updated to Big Sur 11.6. Now it runs at snail pace and spinning beachballs abound.

I want to use an external SSD drive as startup disk to extend the life of my beloved iMac. I would welcome any advice on what drive to buy or whether to buy an enclosure plus SSD cards. Iā€™d like a 2TB drive and for transfer speeds to be as fast as possible. I had hoped to use the Thunderbolt 2 port but, from what research Iā€™ve done, this would appear to be difficult if not impossible.

Any advice welcome.

You can use any TB3 case just fine together with Appleā€™s $49 TB3-TB2 adapter (and TB2 cable). Of course youā€™ll be clipped at 20 GBps by your TB2 bus, but thatā€™s still better than the SSD performance youā€™re getting from your internal as-built config. Added benefit is you can opt for as large capacity as you like with no need to crack open your iMac, plus this storage can be reused again on any future Mac at its full potential if desired.

Thatā€™s not a cheap solution though. Much less expensive would be a SATA SSD in a USB3 enclosure, but at 6 Gbps (best effort) that will not be a performance upgrade over your internal SSD. It really boils down to how much performance you want/need and what youā€™re willing to pay for it. Iā€™d consider how much longer you expect to be able to put this iMac to good use. If it absolutely has to last, Iā€™d bite the bullet. But if youā€™re not so sure about that (and just consider its age), Iā€™d probably suggest saving that money now so you can put it towards a new M1X iMac next spring/summer.

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Thanks for this Simon. I thought the same as you and I have a USB C SSD drive on order with the intention of using the adapter you suggest but others have directed me to the smallprint attached to the adapter. It is not compatible with the iMac I have and an attached USB C drive requires its own power source in order to use the Thunderbolt 2 port. I can find no USB C drives with power supplies available, I wish I could.
If you know differently I would be very pleased to hear back from you.

You only use that adapter for Thunderbolt enclosures.

If OTOH you already have a USB-C enclosure you simply need a USB-C to USB-A cable. Maximum throughput there of course is 5Gbps limited by your USB ports. But truth be told, if youā€™re using a SATA SSD (6 Gbps) youā€™re not losing much.

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But it may be a big improvement over his fusion drive. A 2014 27" iMac has only a 128 GB SSD paired with a 1 TB hard drive. If he opted for the 3 TB fusion drive, then itā€™s a 256 GB SSD.

Depending on usage patterns and how Big Sur manages fusion drives, he may find performance seriously throttled by the HDD, in which case a USB/SATA SSD may still be a big performance improvement.