Upgrading Fusion Intel iMac : most cost effective use of SSD. Advice please.

Thank you for pointing out my error Jack. Yes your LaCie NVMe is about three times faster than my Samsung T7. That would certainly account for your external speed results being better than mine.

However, the TB3 cable is surely a bottleneck regarding speed? 40GB/ps really inhibits the speed potential of both your LaCie and my T7.

As I said above, the direct connection of NVMe to the PCIe/motherboard would ensure a faster performance closer to theoretical speeds than is possible with any external connection. How much faster is an open question. Your experience renders the external vs internal as similar, which is interesting given the unspectacular performance of the Apple SM0128G NVMe, and the high 3000GB/ps speed of the LaCie SSD.

Cost-wise, to get 3000+GB/ps the LaCie you describe is currently close to AUD $600. By comparison the internal OWC Aura Pro X2 NVMe running at 3000+GB/ps can be purchased around AUD $364 from Amazon AU.

In considering speed, I see three factors favouring internal over external NVMe:

1. The internal NVMe will run close to maximum theoretical speeds, whereas the external is partly throttled by the 40GB/ps TB3 cable and by o/s drive manager.
2. An internal OWC Aura X2 NVMe is significantly cheaper than the external LaCie 1TB TB3 although installation is labour intensive for the OWC.
3. Making speed comparisons based on the Fusion Drive vs External should consider the Apple SM0128G is approximately 15%-55% slower than the OWC Aura X2 according to task: https://www.anandtech.com/show/14382/the-owc-aura-pro-x2-ssd-review-nvme-for-older-macs/2 On this basis fitting an internal 3000MB/ps NVMeSSD would seem to raise a Mac performance markedly above any external SSD.

As a result of your comments Jack, as a lay consumer, I have more closely examined the issues and the internal OWC NVMe appeals to me as best value for money so far. Exactly how much speed I may gain is hard to judge and the percentage needs to be considerable to be noticeable. Given the small time spans, and judging from https://www.anandtech.com figures I am guessing at average 50% faster is needed to justify the effort.

Can any reader of this blog offer insight to the speed gain of an internal NVMe running at around 3000MB/ps?

Thank you for your response Jack.

In essense I seek to minimise desk clutter. However I have to disagree with your comment on speed of external drive. I have an external 1TB Samsung T7 connected with TB3. With Monterey as a start-up drive on the Samsung, the time was 42 seconds.

Start-up on the Fusion drive was 20 seconds.

Given the NVMe is in a PCIe slot on the motherboard with no manager or cables involved as is the case with the external drive the disparity in speed is not difficult to understand.

If you are referring to an SSD replacing the Fusion HDD it will be a SATA/SSD at 600 MB/sec. An NVMe SSD is generally quoted as four times faster than the SATA/SSD 3000+/MB/sec. The numbers are bench test speeds.

Given that the Apple NVMe is very average in speed tests, price aside, Purchasing a good quality 1TB NVMe seems to me the most obvious way to improve mac performance.

Thank you for your comments HWTech. I appreciate that embarking upon considerable labour needs to be justified with a marked speed improvement. Your comments about NVMe Gen 2 and external reflect Jack’s observation.

I am assuming the combination of Apple SM0128L and TB3 cable choking external SSD explains the similarity of your speed impressions and Jack-19’s comments.

I would have expected Jack’s LaCie to outperform Apples internal NVMe by a large margin based upon its speed and capacity.

At this stage I have no intention of replacing Apples SATA HDD. But thanks for the caution. I also very much appreciate your comments about the OWC Aura X2 particularly as it seems costly by comparison with its performance specs.

Using a Sabrent NVMe/M2 Gen 3 SSD and a Sintech NGFF Adapter card the guy replaced both NVMe and SATA drives with SSD. He happens to be upgrading exactly my model iMac 19.1 and It was most helpful that he identified the Sabrent SSD’s which proved compatible.

However the jury is still out regarding effect of speed on start-up and video file transfer.

According to Blackmagic my Write/Read speed is around 750/2500 MB/s. Given a faster NVMe at Write speed of say a Samsung Evo or Evo plus giving 2700-3000MB/s improvement, I would expect to see and feel a speed jump.

Has anyone replaced the Apple SM0128L with a fast NVMe and is prepared to comment on apparent speed improvement?

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