Using external USB-C SSD as main drive?

[ondert]

Why in the world would you do that? A SATA III SSD is roughly 1/6 the speed of a fast NVMe 3 x4 blade in a 2015 or later iMac.

If you're going in — or having someone do the work — might as well do the job right.

Because I catched a huge deal from a reseller and they had only stock configurations with fusion drive. Then I brought mine to the reseller and they changed the 2TB 3.5” hdd with a 1TB 2.5” sata ssd.

 

[mikehalloran]

Because I catched a huge deal from a reseller and they had only stock configurations with fusion drive. Then I brought mine to the reseller and they changed the 2TB 3.5” hdd with a 1TB 2.5” sata ssd.

Hopefully, you got a really good price on that. The reseller did tie it back to the blade as a fusion drive, right?

A SATA III SSD is certainly better than the HDD that was taken out.

 

[hobro]

I'm a bit confused by all the information provided here so far.
Anyway: I have a iMac 2017 4K 21.5" with a standard internal HDD. I turned out over time that the machine is significantly slower than the same machine with a fusion drive (I understand the difference and it was a mistake to buy the machine without fusion drive in the first place). Apple NZ offers a "LaCie 500GB Mobile SSD High‑Performance External SSD USB-C USB 3.0".
Can I install Catalina on such an external drive (connected via USB-C) and would make this the machine significantly faster?
Any suggestions are much appreciated!

 

[Fishrrman]

hobro --

Catalina IS NOT going to make the iMac "faster".
In fact, I suggest you stay away from it for a while, and keep using Mojave (which is stable and smooth).

If you want to "make the iMac faster", you have 3 choices:
1. Open it up and put an SSD inside. A risky procedure (unless you're confident and competent working inside Macs), and a 2.5" SATA SSD isn't the "fastest choice". (see #3 below)
2. Attach an external USB3 drive (such as a Samsung t5, there are others), and set that up to be the boot drive. This will give you reads around 430mbps.
3. Attach an external thunderbolt3 drive (to the USBc port), such as the Samsung X5. This will give you reads in the 1,700-2000+mbps range -- VERY fast, equivalent to those you get from an internal SSD. But be aware that these are somewhat more costly than USB3 drives.

 

[hobro]

Thanks for the reply. I did not expect that Catalina makes the iMac faster - If I install the a new OS (on an external drive), it would just be the newest one, but could be Mojave as well.
No - opening the iMac is not an option, so I have a closer look into 2) and 3)

 

[Regbial]

Why in the world would you do that? A SATA III SSD is roughly 1/6 the speed of a fast NVMe 3 x4 blade in a 2015 or later iMac.

If you're going in — or having someone do the work — might as well do the job right.

CAN they actually do that? Or does one have to configure the Mac for SSD out of the box for that to be possible? (Does it com with both a SATA and “blade” port inside??)

Also, are “blade” SSDs longer lasting than SATA ones? I’m worried if I choose the 256gb SSD for my iMac, it will start to die off within 5-8 years. Could it then be replaced??

 

[mikehalloran]

CAN they actually do that? Or does one have to configure the Mac for SSD out of the box for that to be possible? (Does it com with both a SATA and “blade” port inside??)

Also, are “blade” SSDs longer lasting than SATA ones? I’m worried if I choose the 256gb SSD for my iMac, it will start to die off within 5-8 years. Could it then be replaced??

The 2015 model iMac is unique in that Apple designed the bus to accept an NVMe 3/4 blade — but didn't install one. So the SSD only and Hybrid models got a slower blade but can take the fast one without the wake from sleep issues that occur when installing in the 2013–2014 iMacs.

The Samsung 970 EVO(500GB–2TB) and the short Sintech adapter are all you need. There are other fast blades on the market such as the WD Black but the Crucial P1 and Intel 600p are too slow.

Two things. 1) Install the Mac OS from an external drive such as a USB installer. DO NOT CLONE TO INSTALL THE OS BECAUSE THAT CAN CAUSE PROBLEMS. The cloning fanboys will probably jump in to explain why I'm wrong but I'm not and there are some very long threads on this subject. I do it after installation and have never had a problem.

2) Non-Apple NVMe blades do not support Internet Recovery. By having a good backup and a USB installer, this will never ever be an issue. I've serviced more Macs than I can count without referring to my books and the number of times I've done Internet Recovery=0.

If you require extra storage, install a SATA III SSD into the SATA bus (available to 4TB).

Warranties are 5 years — don't buy any that aren't. Always have a good backup. I prefer Time Machine but there's nothing wrong with cloning in this regard—as long as you don't try to install the OS from scratch onto a non-Apple NVMe blade.

 

[Regbial]

The 2015 model iMac is unique in that Apple designed the bus to accept an NVMe 3/4 blade — but didn't install one. So the SSD only and Hybrid models got a slower blade but can take the fast one without the wake from sleep issues that occur when installing in the 2013–2014 iMacs.

The Samsung 970 EVO(500GB–2TB) and the short Sintech adapter are all you need. There are other fast blades on the market such as the WD Black but the Crucial P1 and Intel 600p are too slow.

Two things. 1) Install the Mac OS from an external drive such as a USB installer. DO NOT CLONE TO INSTALL THE OS BECAUSE THAT CAN CAUSE PROBLEMS. The cloning fanboys will probably jump in to explain why I'm wrong but I'm not and there are some very long threads on this subject. I do it after installation and have never had a problem.

2) Non-Apple NVMe blades do not support Internet Recovery. By having a good backup and a USB installer, this will never ever be an issue. I've serviced more Macs than I can count without referring to my books and the number of times I've done Internet Recovery=0.

If you require extra storage, install a SATA III SSD into the SATA bus (available to 4TB).

Warranties are 5 years — don't buy any that aren't. Always have a good backup. I prefer Time Machine but there's nothing wrong with cloning in this regard—as long as you don't try to install the OS from scratch onto a non-Apple NVMe blade.

I see! Thank you so much for clearing all that up. ^_^

Yeah I prefer to just clean install and move stuff as well... always have done it that way. And I always make a separate installer, because of paranoia, no worries.

And I also have Time Machine, it's awesome.

THank you for your helpful advice. Saving it all in a note. 👍

 

[thisisnotmyname]

There are things you don’t understand. 40GB/sec is not possible from any available external storage array currently being made for home use. Check the specs. 40GBs is theoretically possible with 80 SSDs in RAID 0. This also assumes that you could get that data down 4 lanes... and there’s the rub:

TB3 is limited to 4 lanes of data as I wrote earlier. An X5 or any RAID 0 array tops out around 3000mBs — same as the internal speed of a 2017–2019 iMac (or a 2015 upgraded to a 970 EVO). Some claim speeds of 3500mBs — one twin-blade claims up to 4000mBs RAID 0 but I’ve not seen real world speed that fast and no NVMe 3 blades are spec’d to put out 2000mBs to only 2 lanes. A quad-blade RAID 0 array tops out around 1500mBs and uses four 970 EVO blades to get there. JBOD increases capacity but a twin runs half speed and a quad runs 1/4 speed. Look it up. NVMe 4 blades require PCIe 4 motherboards — they run at NVMe 3 speeds otherwise.

Less expensive is to install the blade inside the iMac where it belongs. The price difference between an X5 and a 970 pays for the labor and puts the change in your pocket. $ave more by installing it yourself. Easy.

2015 and later — use a fast blade like a 970 EVO or a WD Blue 3D. Costs more than the ones below but a lot faster.

2013-2014 — an inexpensive, slow blade like a 660p or P1 is fine. The PCIe 3 x1 bus cannot take advantage of the 970 speed.

what?? First off, they said 40 Gb/s not 40 GB/s. Second, TB3 muxes at one end and demuxes at the other and is agnostic to whatever is attached; the storage device can do anything it wants and aggregate 40 Gb/s (minus overhead of the protocol) worth of data through the TB3 pipe. Third, you don't seem to understand RAID and JBOD and are somehow focused on separating out physical lanes of PCIe amongst devices in an array. I personally am saturating TB3 with external storage, it's absolutely doable with the correct gear.

 

[Fliu]

Do people use the Samsung T5, X5, or custom SSD + enclosure continuous as the boot drive?
Any issues there? Do the drives get hot? Does the iMac sleep and wake correctly?