Is a Thunderbolt 2 external SSD faster than an internal Fusion drive?

camner

macrumors regular
Original poster
Jun 19, 2009
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I have a 2015 27" iMac with a 2TB Fusion drive. I also have an OWC 4 bay Thunderbolt 2 external enclosure with a bay I'm not using.

I'm thinking of getting an off-the-shelf (Samsung EVO?) 2TB SSD and sticking in the Thunderbolt enclosure and using the SSD as the boot drive (and, of course, my data drive as well).

I know that the internal bus is faster than TB2, and the HDD part of the Fusion drive is a 7200rpm drive (according to System Information).

Would the external SSD be noticeably faster than the internal Fusion drive?

At this point, I'm not interested in opening up my iMac and replacing the internal HDD with an SSD.
 

nambuccaheadsau

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Oct 19, 2007
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For mine I do not think the setup you describe will be faster than the 128GB Blade Drive, which is blazingly fast, but overall I would estimate the TB2 external SSD would run at some 90% of the speed of the Blade Drive. So in real terms the difference would not be that noticeable.

Any other suggestion would require opening the machine up and I think you are wise looking to avoid that. I know, I know. Some smarties can do it but it is not for all of us.
 

Hater

macrumors 6502a
Sep 20, 2017
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Edinburgh, Scotland
you'd be better off splitting the fusion drive, buying a 2TB NVMe drive and replacing the internal 128GB blade drive with a 2TB blade drive, and just using the fusion drive as two seperate drives.

can replace the spinning part of the fusion drive with an SSD as well if you want for two internal SSD's.

whoops, just read your last line. why? it's not hard, and i'm assuming your machine is already out of warrenty anyway. so much nicer than some dumb external enclosure.
 

camner

macrumors regular
Original poster
Jun 19, 2009
126
0
For mine I do not think the setup you describe will be faster than the 128GB Blade Drive, which is blazingly fast, but overall I would estimate the TB2 external SSD would run at some 90% of the speed of the Blade Drive. So in real terms the difference would not be that noticeable.

Any other suggestion would require opening the machine up and I think you are wise looking to avoid that. I know, I know. Some smarties can do it but it is not for all of us.
I'm not expecting to beat out the 128GB blade drive, but obviously the bulk of the data (videos and photos are mainly of interest) have to be on the HDD, right? I'm assuming that the Fusion drive software has already made sure that the OS is on the blade and not on the HDD.

Is there any way to tell what is on the HDD and what is on the SSD?

Another option would be to break the Fusion drive, put the OS on the 128GB blade, and use the external TB enclosure with an 2TB SSD to hold everything else. I just don't know if the speed gains by doing that is worth the cost of the SSD, or whether I might as well keep the Fusion drive the way it is.
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you'd be better off splitting the fusion drive, buying a 2TB NVMe drive and replacing the internal 128GB blade drive with a 2TB blade drive, and just using the fusion drive as two seperate drives.

can replace the spinning part of the fusion drive with an SSD as well if you want for two internal SSD's.

whoops, just read your last line. why? it's not hard, and i'm assuming your machine is already out of warrenty anyway. so much nicer than some dumb external enclosure.
Well, I bought the iMac refurbished from Apple in 2017 and also purchased AppleCare, so it IS still under warranty (I've already gotten my $$ worth for the AppleCare because the HDD went belly up at about the 1.5 year mark), so I'm not ready to open the iMac just yet. (I asked the Apple Store if they'd put in a 2TB SSD when the HDD needed to be replaced, if I bought it and they said no, not under the warranty coverage.)
 

Fishrrman

macrumors P6
Feb 20, 2009
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OP:

Don't get an external thunderbolt drive.
You can achieve the same speeds, at less cost, by buying a USB3 SSD and using that instead.
A USB3 SSD might even be FASTER THAN a thunderbolt SSD.

I'd be looking at one of these:
https://www.amazon.com/SanDisk-1TB-Extreme-Portable-SDSSDE60-1T00-G25/dp/B078STRHBX/ref=sr_1_2?s=electronics&ie=UTF8&qid=1541356729&sr=1-2&keywords=sandisk+extreme+usb+3+portable+drive

Having said that...

If you want THE FASTEST drive possible, the internal SSD portion of the fusion drive will be faster than any external SSD you can attach, IF you "de-fuse" the internal fusion drive and then run the SSD as a "standalone SSD".

Of course, it will only be 128gb in size, but that's still large enough for the OS, apps, and basic accounts (you would want to keep large libraries of stuff like movies, music and pictures on the internal HDD).

You must (of course) back up the fusion drive first, because "de-fusing" it will wipe out any data on it.
But the speed increase you'll get from running it as "two separate drives" will be worth the trouble.
 

mikehalloran

macrumors 68000
Oct 14, 2018
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[doublepost=1541608840][/doublepost]
you'd be better off splitting the fusion drive, buying a 2TB NVMe drive and replacing the internal 128GB blade drive with a 2TB blade drive, and just using the fusion drive as two seperate drives.

can replace the spinning part of the fusion drive with an SSD as well if you want for two internal SSD's.
The simple answer is that a RAID array can approach the speed of the 128G NVMs PCIe 2 blade only. It cannot be done with a single drive. That's pretty expensive.

Far less expensive is to replace the blade with a Samsung 970 EVO. You can get a 2T plus the pin-out adapter under $600 if you shop around. An experienced Mac tech will charge an hour labor to do the job and it will take him/her less time than that.

Not only is it far less expensive but a 970 is PCIe 3x4 (aka quad) like the quad buss in a 2015 iMac. Yes, Apple put a half-speed chip in the 2015–2016. You can correct this or have it done.

By all means, replace that spinning heat pump (HDD) at the same time. Your iMac will run cooler and last longer. A SATA III SSD ranges from $150 for 1T to $790 for 4T with the sweet spot for most users being $315 or so for a 2T with a 5 year warranty (many brands).

In the Silicon Valley where I live, the going labor rate for this job averages $75.
[doublepost=1541610381][/doublepost]Do not buy the OWC Aura blade for these. There's a reason why OWC lists them for the Mac Pro 6.1 and their RAID arrays only.

Not only are these far more expensive than the 970 EVO but they are the slower PCIe 2 — just like the Mac Pro. In addition, many have glued on heat sinks that make them too thick to fit behind the right speaker in an iMac. This is not the case with the faster, less expensive 970 EVO (the speaker has to be loosened to slide in the adapter but then it tightens without interference).

One can speculate all day long why the Mac Pro buss didn't get a bump to PCIe quad in 2015 like the MacBook Pro and iMac. I'm guessing that its heat dissipation issues are the reason. MPs have major issues under heavy loads in this regard.
 
Last edited:

camner

macrumors regular
Original poster
Jun 19, 2009
126
0
OP:

Don't get an external thunderbolt drive.
You can achieve the same speeds, at less cost, by buying a USB3 SSD and using that instead.
A USB3 SSD might even be FASTER THAN a thunderbolt SSD.

I'd be looking at one of these:
https://www.amazon.com/SanDisk-1TB-Extreme-Portable-SDSSDE60-1T00-G25/dp/B078STRHBX/ref=sr_1_2?s=electronics&ie=UTF8&qid=1541356729&sr=1-2&keywords=sandisk+extreme+usb+3+portable+drive
Well, I already have the external Thunderbolt enclosure (I've been using it for Time Machine backups and for another local backup...a daily clone), so that's a sunk expense.

But, why would USB3 be faster than Thunderbolt 2?

Finally, I've found that there are times when an external drive connected via USB3 sometimes will be disconnected when the iMac wakes from sleep, whereas this simply never happens with the Thunderbolt 2 enclosure.
 

mikehalloran

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Oct 14, 2018
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Well, I already have the external Thunderbolt enclosure (I've been using it for Time Machine backups and for another local backup...a daily clone), so that's a sunk expense.
Sunk expense? No. A Time Machine backup? Yes, you still need that. A daily clone plus time Machine... let's save that for another thread.

But, why would USB3 be faster than Thunderbolt 2?
It isn't.

Finally, I've found that there are times when an external drive connected via USB3 sometimes will be disconnected when the iMac wakes from sleep, whereas this simply never happens with the Thunderbolt 2 enclosure.
Yep.

The answer to the original question is No. No faster.

Least expensive way to get what you want: Open it up and upgrade the internal storage. Quieter and faster, too.

There are many ways to rephrase and re-qualify this question. The answer won't change.
 

imageWIS

macrumors 65816
Mar 17, 2009
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NYC
you'd be better off splitting the fusion drive, buying a 2TB NVMe drive and replacing the internal 128GB blade drive with a 2TB blade drive, and just using the fusion drive as two seperate drives.

can replace the spinning part of the fusion drive with an SSD as well if you want for two internal SSD's.

whoops, just read your last line. why? it's not hard, and i'm assuming your machine is already out of warrenty anyway. so much nicer than some dumb external enclosure.
I thought the iMacs NVMe was soldered on and had a proprietary connector?
 

mikehalloran

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not in the 2015s.
Or any other year (the iMac Pro does not use NVMe so doesn't count)

There is a proprietary pin-out, that's all. A $6–$13 adapter corrects this. The part is the same, where you buy it is the only difference.

The NVMe is not soldered into any Mac (we think. Waiting on iFixIt to tear down the new Mini).

A Samsung 970 EVO, paired with that adapter, will fit any 2013-on Mac Pro, iMac and portable. It will not give PCIe quad speed on any Mac with the slower PCIe 2 buss such as the Mac Pro 6.1 and 2013–2014 portables.
 

camner

macrumors regular
Original poster
Jun 19, 2009
126
0
The answer to the original question is No. No faster.
.
Just to be crystal clear: You are saying that an external SSD in a Thunderbolt 2 enclosure would NOT be faster than the existing Fusion drive. Yes?

Thanks for your responses.
 

mikehalloran

macrumors 68000
Oct 14, 2018
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Just to be crystal clear: You are saying that an external SSD in a Thunderbolt 2 enclosure would NOT be faster than the existing Fusion drive. Yes?

Thanks for your responses.
Just to be absolutely, crystal clear, make no mistake, please read this slowly so that you understand...

If you fill this

I also have an OWC 4 bay Thunderbolt 2 external enclosure with a bay I'm not using.
with four SSDs, you may get as fast — but only if it's the version that takes NVMe 2 SSDs and you install 4 identical drives (970 EVO 1T x4 @ $227 = $908; 2T x4 @ $559 = $2,236) and configure to RAID 0
https://www.amazon.com/OWC-Express-4M2-4-Slot-NVMe-Enclosure/dp/B07G5MHBW1
That's pretty damned expensive for 1T or 2T external storage. Yes, there are other RAID configurations that give you more storage from the same chips but they are slooooower.

If your OWC 4 bay Thunderbolt 2 external enclosure is not NVMe (they do/did make others), it cannot be as fast no matter how you set it up.

Here's the fun part. I'll put it in caps.

IF YOU TAKE ONE 970 EVO AND PUT IT INSIDE YOUR 2015 IMAC, THE PCIe BUSS WILL RUN TWICE AS FAST AS THE ORIGINAL APPLE SSD.

You will need an inexpensive adapter ($6–$13) and someone to install it ($75) if unwilling to tackle it yourself. Yes, you can get a 970 as small as $89 for a 250G but why?

Bottom line: The OWC 4 bay Thunderbolt 2 external enclosure — whatever version it is — makes for great external storage. There's certainly no need for RAID 0.

But... A SATA III SSD is half the price of a 970 and can be installed in place of the HDD inside your iMac causing it to run faster, cooler and longer. Heat is the enemy of components and that spinning motor runs very hot.

There are RAID arrays you can buy that can be as fast but you don't own one and it will be very expensive.
 

imageWIS

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Mar 17, 2009
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Or any other year (the iMac Pro does not use NVMe so doesn't count)

There is a proprietary pin-out, that's all. A $6–$13 adapter corrects this. The part is the same, where you buy it is the only difference.

The NVMe is not soldered into any Mac (we think. Waiting on iFixIt to tear down the new Mini).

A Samsung 970 EVO, paired with that adapter, will fit any 2013-on Mac Pro, iMac and portable. It will not give PCIe quad speed on any Mac with the slower PCIe 2 buss such as the Mac Pro 6.1 and 2013–2014 portables.
Great, thanks. Been thinking about upgrading the Fusion Drive in my late 2015 5K 27", but not sure if too keep the 128GB NVMe and just add a SATA SSD or replace the NVMe for something later and leave the SATA free or add a smaller SSD...?
 

IngerMan

macrumors 65816
Feb 21, 2011
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Great, thanks. Been thinking about upgrading the Fusion Drive in my late 2015 5K 27", but not sure if too keep the 128GB NVMe and just add a SATA SSD or replace the NVMe for something later and leave the SATA free or add a smaller SSD...?

I have thought about doing this with my 27" 2TB fusion Late 2015. But honestly I don't think its going to make much difference in performance. I still have 6th generation Skylake 3.3 processor. I still have the weak M395 GPU. I still have a machine that performs in middle standards to the new 8th generation, I doubt it will raise the bar that would be noticeable for me.

I will just plan on another Desktop upgrade in a few more years and save my money for the time being.
 

brucebrendon

macrumors regular
Mar 30, 2007
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My friend has a 2012 27" iMac that had a useless FusionDrive in it. They also had a 2tb Thunderbolt LaCie they were using for backups.

I put a £80/£90 (Patriot Burst) 1tb SSD in the LaCie enclosure and everything was back to good.

It's not NVMe speeds, but the Fusion was useless with professional CC (esp Photoshop) work, probably due to super slow Scratch issues.

The Thunderbolt SSD has the OS, APPs and working files. The internal old Fusion is now a TimeMachine Backup. The 2tb HDD from the LaCie is now in a USB 2.0 enclosure. I didn't want to go USB for the SSD due to it being the boot drive, which would have a delay seeing the USB bus.

As said – it's certainly no NVMe, but they're now very please with the useable 2012 machine it should have been to start with (without taking the screen off, just a screwdriver).
 

Fishrrman

macrumors P6
Feb 20, 2009
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bruce wrote:
"The internal old Fusion is now a TimeMachine Backup."

This is THE WRONG WAY TO DO IT.

The internal drive should be fully bootable to the finder.
What if the external drive fails?
There will be no way to "boot to the finder".

The BETTER WAY TO DO IT:
Use either CarbonCopyCloner or SuperDuper to clone the contents of the external boot drive to the internal fusion drive.

Now -- if something ever goes wrong with the external drive -- the owner can be "up and running" again in the time it takes to reboot.

THIS IS NOT POSSIBLE WITH A TM BACKUP.

And we know the external drive will never fail -- right?
 
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GumaRodak

macrumors member
Mar 14, 2015
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Check samsung x5 external drive or sandisk 900 external drive...bith are external ssd via usb connection...around 800mb/s speed
 

Ledgem

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Check samsung x5 external drive or sandisk 900 external drive...bith are external ssd via usb connection...around 800mb/s speed
The X5 is a Thunderbolt 3 drive. Unfortunately for those of us on older systems, Thunderbolt 3 drives tend to receive their power through the Thunderbolt 3 port. While Apple has a Thunderbolt 2 to Thunderbolt 3 adapter, it only carries data and not power. So we can't use Thunderbolt 3-based drives.

The original post is already almost one year old, so I'd guess that camner already came up with a solution. Reading over these replies, though, I think people are forgetting that the 2015 iMac (which is also my model) is USB 3.0, not USB 3.1. That's 5 Gbps compared with Thunderbolt 2's 20 Gbps. USB 3.0 is still decent but that's a pretty significant difference. If someone already has Thunderbolt 2 peripherals to make use of and doesn't care to mess with the internals of their computer, it seems an obvious choice over USB.
 
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mikeboss

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While Apple has a Thunderbolt 2 to Thunderbolt 3 adapter, it only carries data and not power. So we can't use Thunderbolt 3-based drives.
Apple's TB3 <-> TB2 adapter does carry power. but only when using TB2 devices connected to a host equipped with TB3.
 

gnasher729

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Nov 25, 2005
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I have a 2015 27" iMac with a 2TB Fusion drive. I also have an OWC 4 bay Thunderbolt 2 external enclosure with a bay I'm not using.
Since the enclosure costs you nothing, and the drive isn't too expensive, you'll get excellent value for money. If you had to spend money, I'd probably buy a USB case instead, but that's pointless since you have the Thunderbolt enclosure already.

And it will be faster than the Fusion drive if you handle huge amounts of data, or when you handle data that hasn't been used for a while, so overall it will beat the Fusion drive.

If you run benchmarks for a living then you can get a faster drive for more money. If you do normal things, this setup will be fast.
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In that case maybe a lacie 5big tb2 which can speed up to 1500mb/s ... but its pricey :)
Especially compared to an enclosure that OP has already sitting around, doing nothing.