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smurray

macrumors regular
Original poster
May 12, 2008
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How much of a speed loss would there be if I were to use an external SSD as the system drive on my 2017 iMac as opposed to an internal SSD? I could hook the external drive up via whatever the faster input method would be (Thunderbolt 3 or USB 3.1 I assume).
 
Over TB3, it really depends on which drive you buy.

For example, this one claims performances close to the internal drive: https://www.bhphotovideo.com/c/product/1294391-REG/lacie_stff2000400_2tb_bolt_3_thunderbolt.html.

But it is 2k so an internal one would be cheaper. A samsung 950 would probably get you about 1.5Gbps compared to 3Gbps for the internal.

I was thinking more about buying an empty enclosure and installing an internal SSD in it. I wasn’t sure what the speed differences there is between the external input options vs an internal drive.
 
TB3 has a max speed of 40Gbps. The limiting factor really is the enclosure and the ssd you put in it.

The internal drives Apple use are very fast, 3Gbps. While there are ways to get that speed in an external enclosure, cost efficient options would get you around 0.5Gbps, while slower it's fast enough for most needs.
 
I was thinking more about buying an empty enclosure and installing an internal SSD in it. I wasn’t sure what the speed differences there is between the external input options vs an internal drive.

Well a PCIe drive on thunderbolt 3 in theory could run as fast as the internal but cost way more than just buying a mac with the drive you needed. A USB 3 sata connected drive will top out at 450 -600MB/s sequential read write speeds so similar to sata connected internal devices, to be honest unless you are constantly moving huge files around you probably won't notice to much difference.
 
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What are u trying to do though? If word and PowerPoint are your only apps I might not notice the difference between 600mbs and a 3gbs true internal. I ran a 2012 iMac with a bad hd using a USB connected sd, never saw an issue.
 
Cheapest, easiest route -- and still QUITE FAST -- would be a Samsung t5 drive.
Quite an elegant little package, too.

I believe there are now appearing USB3.1 gen2 externals (via USB-c), but they will cost somewhat more money.

I WOULD NOT open a 2017 iMac to install an internal drive.
Warranty.... warranty... warranty!
 
It’s not about Thunderbolt or USB ... they just provide the “road” for info from SSD. The speed depends more on the SSD kind. A SATA 2.5” SSD can give about 500Mb read/write (as written before in thread).
A PCI-e SSD will be near 2000Mb read/write.
Sonnet has just released a 1Tb bus powered Thunderbolt3 portable SSD which offers such good speed (comparable to internal Apple SSD). It will cost you about 1000$.
Getting a usb3 or usb3.1 enclosure for a SATA SSD is much cheaper (I can’t find “pure” Thunderbolt cases or disks. Samsung T5 is said to be Thunderbolt... but if you read footnotes, you’ll find it’s usb3.1. Maybe I’m mistaken... All this thing is a little bit confusing. Anyhow, even usb3 gives you enough “road” for what the SSD can give).
Just remember to get a case that supports UASP protocol, as it makes disk speedier.
 
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Here you get an idea. This is my three weeks old 27" iMac 5K mid-2017 with i5 3.5GHZ, 24GB RAM, Radeon 575 and 512 SSD. The external drive is a 1TB Glyph Atom RAID SSD which is one of the fastest SSD in the market. It's USB 3.1 Gen 2 so it connects to the Thunderbolt 3 port of my iMac.

Glyph Atom RAID 1TB SSD - USB 3.1 Gen 2
Screen Shot 2017-11-23 at 9.22.22 AM.png


Internal 512GB SSD (27" iMac 5K mid-2017)
Screen Shot 2017-11-23 at 9.21.30 AM.png


Just for the sake of comparisons, here is the speed of my 4TB G-Drive USB-C external drive. Check that both, the Glyph Atom RAID SSD and the G-Drive are connected to the Thunderbolt 3 ports on my iMac.

Screen Shot 2017-11-23 at 9.33.53 AM.png
 
I can’t find “pure” Thunderbolt cases or disks.

I've owned and used the Delock 42510 Thunderbolt 1 enclosure for a few years now. I use it with a 500GB Samsung 840 EVO. It was the boot disk for my former Late 2013 iMac and is now dedicated to BootCamp. It is well-designed, sturdy, reliable and still going strong almost four years later.

Delock has now released the new $89 Thunderbolt 3 (USB-C) 42555 enclosure! I might get one to review.

*** Update *** It seems like the new 42555 enclosure may actually just be compatible with the Thunderbolt 3 interface while it doesn't actually have a Thunderbolt controller. It seems to be USB3.1 Gen 2 for the 10GB/s throughput so I still recommend the 42510 above for those looking for the benefits of a true Thunderbolt device. (TRIM, etc). Note that you will also need a Thunderbolt 2 to Thunderbolt 3 adapter as well.
 
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I've owned and used the Delock 42510 Thunderbolt 1 enclosure for a few years now. I use it with a 500GB Samsung 840 EVO. It was the boot disk for my former Late 2013 iMac and is now dedicated to BootCamp. It is well-designed, sturdy, reliable and still going strong almost four years later.

Delock has now released the new $89 Thunderbolt 3 (USB-C) 42555 enclosure! I might get one to review.

*** Update *** It seems like the new 42555 enclosure may actually just be compatible with the Thunderbolt 3 interface while it doesn't actually have a Thunderbolt controller. It seems to be USB3.1 Gen 2 for the 10GB/s throughput so I still recommend the 42510 above for those looking for the benefits of a true Thunderbolt device. (TRIM, etc). Note that you will also need a Thunderbolt 2 to Thunderbolt 3 adapter as well.
Do you see...? You point us to a “Thunderbolt compatible” case, that works in usb3.1 gen2. It keeps being confusing. This new case gives a “road” for 10Gb/s (usb3.1)... no 40Gb/s as Thunderbolt 3 gives.
As I said, even usb3.0 is enough, so, ok: Thunderbolt COMPATIBLE case.
I really don’t understand all this fuzz & misinformation.
 
Do you see...? You point us to a “Thunderbolt compatible” case, that works in usb3.1 gen2. It keeps being confusing. This new case gives a “road” for 10Gb/s (usb3.1)... no 40Gb/s as Thunderbolt 3 gives.
As I said, even usb3.0 is enough, so, ok: Thunderbolt COMPATIBLE case.
I really don’t understand all this fuzz & misinformation.

As I very clearly stated, the $85 Delock 42510 is an extremely reliable 2.5" THUNDERBOLT enclosure which I have personally owned and used for several years now. It is not Thunderbolt-3, but first generation. I posted about it in reply to your comment that you couldn't find pure Thunderbolt cases.

I cannot say for sure about the newer Delock model because I do not own it yet.

What misinformation?
[doublepost=1511525732][/doublepost]Here's a head-to-head comparison/review I did with the Delock 42510 and an Inateck bus-powered UASP USB3 enclosure three and a half years ago for some idea of its performance.

The clear advantage of using Thunderbolt for external boot drives is that it is an extension of the PCI bus and thus users can enable TRIM and run firmware updates, neither of which are possible over USB. It also makes BootCamp much easier since Windows cannot be easily installed to USB drives without workarounds. TRIM greatly reduces write amplification which boosts performance and can also extend the life of a drive.
 
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As I very clearly stated, the $85 Delock 42510 is an extremely reliable 2.5" THUNDERBOLT enclosure which I have personally owned and used for several years now. It is not Thunderbolt-3, but first generation. I posted about it in reply to your comment that you couldn't find pure Thunderbolt cases.

I cannot say for sure about the newer Delock model because I do not own it yet.

What misinformation?
[doublepost=1511525732][/doublepost]Here's a head-to-head comparison/review I did with the Delock 42510 and an Inateck bus-powered UASP USB3 enclosure three and a half years ago for some idea of its performance.

The clear advantage of using Thunderbolt for external boot drives is that it is an extension of the PCI bus and thus users can enable TRIM and run firmware updates, neither of which are possible over USB. It also makes BootCamp much easier since Windows cannot be easily installed to USB drives without workarounds. TRIM greatly reduces write amplification which boosts performance and can also extend the life of a drive.
I remark “misinformation” from vendors, not from you (some of the things I know, I’ve learned from your posts). You write you can’t say for sure about the newer Delock model Thunderbolt capabilities. Well... They give info in their web!! Don’t you find it not so clear as it could be? Don’t you think that vague Thunderbolt compatibility (compatibility or functionality?) info is intended?
That’s what I call misinformation.
 
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I remark “misinformation” from vendors, not from you (some of the things I know, I’ve learned from your posts). You write you can’t say for sure about the newer Delock model Thunderbolt capabilities. Well... They give info in their web!! Don’t you find it not so clear as it could be? Don’t you think that vague Thunderbolt compatibility (compatibility or functionality?) info is intended?
That’s what I call misinformation.

Yes, I see what you mean now. Sorry that I misinterpreted your comments. The fact that USB-C and Thunderbolt-3 now use the same connector has led to this confusion not just with the Delock but with a lot of new devices.

Marketing USB 3.1 devices as Thunderbolt-3 compatible may not be misinformation but it can certainly cause customers to be misled into thinking that they are getting something that they aren't.
 
Yes, I see what you mean now. Sorry that I misinterpreted your comments. The fact that USB-C and Thunderbolt-3 now use the same connector has led to this confusion not just with the Delock but with a lot of new devices.

Marketing USB 3.1 devices as Thunderbolt-3 compatible may not be misinformation but it can certainly cause customers to be misled into thinking that they are getting something that they aren't.

Correct me if I’m wrong: ALL USB devices are “Thunderbolt 3 compatible”... with the appropriate connection wire.
;-D
Makers & vendors are using an intendedly confusing term to sell “thunderbolt disks”. Some of them DO give a very clear info when the product is a real Thunderbolt device: https://www.sonnetstore.com/products/fusion-tb3-pcie-flash-drive-1tb
 
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I've owned and used the Delock 42510 Thunderbolt 1 enclosure for a few years now. I use it with a 500GB Samsung 840 EVO. It was the boot disk for my former Late 2013 iMac and is now dedicated to BootCamp. It is well-designed, sturdy, reliable and still going strong almost four years later.

Delock has now released the new $89 Thunderbolt 3 (USB-C) 42555 enclosure! I might get one to review.

*** Update *** It seems like the new 42555 enclosure may actually just be compatible with the Thunderbolt 3 interface while it doesn't actually have a Thunderbolt controller. It seems to be USB3.1 Gen 2 for the 10GB/s throughput so I still recommend the 42510 above for those looking for the benefits of a true Thunderbolt device. (TRIM, etc). Note that you will also need a Thunderbolt 2 to Thunderbolt 3 adapter as well.


I also used a Thunderbolt 2 RAID case with my 2014 iMac 5K for several years now with the advantages you described but with the limitation of the SATA interface to the SSDs. So even in a RAID 0 configuration it did not run over about 440 MB/sec. What I am hoping for is an empty Thunderbolt case with M.2 interfaces for NVMe drives. That would show the real potential of the Thunderbolt interface....
 
I also used a Thunderbolt 2 RAID case with my 2014 iMac 5K for several years now with the advantages you described but with the limitation of the SATA interface to the SSDs. So even in a RAID 0 configuration it did not run over about 440 MB/sec. What I am hoping for is an empty Thunderbolt case with M.2 interfaces for NVMe drives. That would show the real potential of the Thunderbolt interface....
There are pci-e cases with Thunderbolt interface. And there are pci cards with the special purpose of allocating up to 4 m2 cards by plugging them in.
Hope that helps you in your search.
http://barefeats.com/hard226.html
 
There are pci-e cases with Thunderbolt interface. And there are pci cards with the special purpose of allocating up to 4 m2 cards by plugging them in.
Hope that helps you in your search.
http://barefeats.com/hard226.html

Thanks, the Nestor case looks from the specs exactly what I was looking for. But this thing is very ugly and very expansive and I can't by it Germany. Are there any alternatives for this kind of case?
 
I am thinking about a similar question. I plan to get an iMac Pro once it is out. I think I will love the speed of its internal SSD, but the space will be too small. I have budget for external SSD(s), and I want it to be as fast as possible.

I am looking into the 4-bay TB3 enclosure by AKiTio. With RAID0, in principle, one should reach 2000MB/s, since an SSD can have roughly 500MB/s. Unfortunately, AKiTiO claimed that their TB3 enclosure can only reach somewhere between 1000MB/s and 1500MB/s, because of the limit between the PCIe and SATA (I don't quite understand this part). This is fast, but not as fast as what I was hoping for.

What I am thinking now is to get two or even three such 4-bay TB3 enclosures and put 8 or 12 SSDs in them with RAID0. Hopefully this will give me something as fast as the internal SSD in an iMac Pro.

Other than the terrible cost, do you guys see any problems in doing so?
 
Cheapest, easiest route -- and still QUITE FAST -- would be a Samsung t5 drive.
Quite an elegant little package, too.
Agreed! I just added an external T5 to the latest model Mac Mini. The T5, connected over USB, is 8 times faster than the internal hard drive.
 
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I’m waiting the postal arrive of a dual-bay dock: https://www.amazon.com/Wavlink-External-Docking-Station-UASP-Black/dp/B019DNBU7G
I must confess I was mistaken at first, thinking it was a Thunderbolt device, but it’ll be fast enough for my needings. I have to rescue an internal HD from my broken “late2009” iMac (new iMac is coming home, also! Internal ssd 1Tb: at the end, you find it reasonably priced knowing the alternatives) and plan to get external SSDs as needed.
Samsung T5 is a nice disk, and adds portability (that I don’t need), but it’s not difficult to find cheaper barebones ssd’s and put them in a case, reaching same speed (400-500mb/s max.).
The RAID 0 solution is said to be more insecure, as if one of the disks fails, all info is lost. I’m not quite sure about this... and has to be with probability, but multiplaying number of disks in RAID 0 is supposed to increase failure prob. There’s an external portable disk in the mood of T5 (Sandisk 900) using this trick to achieve almost 900mb/s.
Anyhow, is nice to think better solutions to reach same speed as internal PCIe ssd will be in the market in near future...
 
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I am thinking about a similar question. I plan to get an iMac Pro once it is out. I think I will love the speed of its internal SSD, but the space will be too small. I have budget for external SSD(s), and I want it to be as fast as possible.

I am looking into the 4-bay TB3 enclosure by AKiTio. With RAID0, in principle, one should reach 2000MB/s, since an SSD can have roughly 500MB/s. Unfortunately, AKiTiO claimed that their TB3 enclosure can only reach somewhere between 1000MB/s and 1500MB/s, because of the limit between the PCIe and SATA (I don't quite understand this part). This is fast, but not as fast as what I was hoping for.

What I am thinking now is to get two or even three such 4-bay TB3 enclosures and put 8 or 12 SSDs in them with RAID0. Hopefully this will give me something as fast as the internal SSD in an iMac Pro.

Other than the terrible cost, do you guys see any problems in doing so?

SSDs with SATA interfaces are a thing of the past....SATA was developed for hard disks with a limit of about 550 MB/s. It does not make sense to use them even in a RAID 0 these days if you can buy the major brands and models as NVMe's too. So something like this Nestor case with NVMe interfaces for the M.2 form factor should be the standard in 2017. This is the same way Apple in doing this for their internal NVMe's for the last several years....
 
So something like this Nestor case with NVMe interfaces for the M.2 form factor should be the standard in 2017. This is the same way Apple in doing this for their internal NVMe's for the last several years....

Do you mean Apple is using RAID 0 as Mac SSD? In such a case, where is the proof of it? On the other hand, the company is not "Nestor" but NetStor Technology. Thanks.
 
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Do you mean Apple is using RAID 0 as Mac SSD? In such a case, where is the proof of it? On the other hand, the company is not "Nestor" but Netstor Technology. Thanks.

Sorry for the typo...I mean that Apple is using NVMe's with a PCIe bus instead of SATA SSD's. This Netstor case is one of the few that is using the same concept (but with only X2 speed) and delivered comparable performance to the internal NVMe storage. This RAID 0 feature is only an optional software RAID and not that important for me....
 
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