Thunderbolt 2 and Thunderbolt 3

jbuhler

Senior Member
I'm on an iMac with Thunderbolt 2. My thunderbolt dock that I used to serve most of my samples and also run an additional monitor just went kaputt and I'm looking to replace its functionality. Thunderbolt 2 devices are getting harder to find. I've been told if you buy one of those very expensive Thunderbolt 2 to Thunderbolt 3 (USB-C) converters that you can run thunderbolt 3 devices at thunderbolt 2 speeds. I'm wondering if anyone here has tried it. Can you daisy chain thunderbolt 3 devices using the one bridged thunderbolt 3 device? Will video pass along the chain as it did with Thunderbolt 2?

My plan right now is to buy the TB3 a Black Magic SSD dock, attach a Thunderbolt 2 to Thunderbolt 3 adapter to it and then run a monitor from the second thunderbolt 3 port on the Black Magic dock. Does that seem like it will work?
 

Virtuoso

Socially Distant Member
No - the Multidock 10G is USB-C, not Thunderbolt 3. Although they use the same connector, they are not the same thing (Yay for standards! o_O). The two rear ports are so that you can split the 4 disks and use them with 2 workstations independently.

The older (and faster - 20Gb vs 10Gb) Multidock 2 however is TB2 and should work fine for what you need. And you won’t need an adapter.
 
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jbuhler

jbuhler

Senior Member
No - the Multidock 10G is USB-C, not Thunderbolt 3. Although they use the same connector, they are not the same thing (Yay for standards! o_O). The two rear ports are so that you can split the 4 disks and use them with 2 workstations independently.

The older (and faster - 20Gb vs 10Gb) Multidock 2 however is TB2 and should work fine for what you need. And you won’t need an adapter.
Thanks so much for answering! I'm getting contradictory answers on this. I also posted the query on Amazon and received two diametrically opposed answers from two sellers, one saying BMD confirmed it will work. An answer on the BMD forum only says that you won't have full functionality (which you wouldn't expect with a TB2 port into the computer).

The older TB2 multidock is not readily available and often sells at a steep premium.

The manual on the BMD site is horrible because it does not really distinguish the two systems in the manual.

I ended up ordering but if it doesn't pass a signal through then it won't work for what I need, so I guess I'll just send it back.
 
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jbuhler

jbuhler

Senior Member
TB2 in general has recently just become very difficult to find, and the confusion between UCB-C and TB3 makes it hard to know what peripherals will work with the older computers, even using the very expensive TB2 to TB3 adapter.
 

dflood

Active Member
I’m in the same situation but can’t offer any guidance. My old T2 drives are getting full and tired. I have been assuming that if you use a Thunderbolt 2 to Thunderbolt 3 adaptor to connect to a peripheral USB-C port rather than an actual Thunderbolt 3 one, it just won’t work. I’ll be interested to hear how you make out. I don’t really want to buy a T2 replacement drive or dock, even if I can find one, since it will probably outlive my current Mac.
 
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jbuhler

jbuhler

Senior Member
I’m in the same situation but can’t offer any guidance. My old T2 drives are getting full and tired. I have been assuming that if you use a Thunderbolt 2 to Thunderbolt 3 adaptor to connect to a peripheral USB-C port rather than an actual Thunderbolt 3 one, it just won’t work. I’ll be interested to hear how you make out. I don’t really want to buy a T2 replacement drive or dock, even if I can find one, since it will probably outlive my current Mac.
From reading around tonight it seems like the TB2/TB3 converter generally works on TB3 stuff but at TB2 specifications. For docks, drive bays, and so forth. Most of those explicitly say a converter will work with limitations. The problem with the new BMD Multidock is that it doesn't seem to offer TB3 through—It's USB-C so even if it works, you'd have to put a TB3 hub before it and then run USB-C from the hub to the Multidock if you also needed to run a monitor from that TB2 port. I'm not sure that combination would work, since at least some of the USB-C ports on TB3 hubs seem to be part of the functionality that doesn't work with TB2—something to do with the power, if I understand it correctly. In any case, I'll be sending the Multidock right back and look out for a deal on a TB2 Multidock, or at least an occasion where I'm not paying too much more for it.
 

Loïc D

Monkeying with libraries
Same boat here. I was thinking getting a CalDigit TS3 pro (USB-C/TB3) and hook it to my old MBPr 2013 using a TB3/TB2 (expensive) cable.
There was no deal on CalDigit products on Black Friday, so I passed (I'm not such in hurry).
Switching to TB3 is also paving the way to the new MBP I plan to buy next year.
 
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jbuhler

jbuhler

Senior Member
Same boat here. I was thinking getting a CalDigit TS3 pro (USB-C/TB3) and hook it to my old MBPr 2013 using a TB3/TB2 (expensive) cable.
There was no deal on CalDigit products on Black Friday, so I passed (I'm not such in hurry).
Switching to TB3 is also paving the way to the new MBP I plan to buy next year.
It is all so confusing because the ad copy uses USB-C and TB3 almost interchangeably. But it’s not clear if the TB2/TB3 adapter works for USB-C. Meanwhile native TB2 has all but disappeared from the market... I’m not sure if that’s because the adapter works really well or if the market for native TB2 is too small.
 

JT

Senior Member
I've run into the same problem. The T2 to T3 adapter allows you to use an older T2 device and connect it to a new Mac with T3 ports, unless I'm mistaken.

But I need the opposite, a way to connect a new T3/USB-C SSD to a T2 port.
 
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jbuhler

jbuhler

Senior Member
I've run into the same problem. The T2 to T3 adapter allows you to use an older T2 device and connect it to a new Mac with T3 ports, unless I'm mistaken.

But I need the opposite, a way to connect a new T3/USB-C SSD to a T2 port.
From the comments on various internet fora, it seems the adapter works both ways. (Read the comments and product descriptions on TB3 products on Amazon for instance. This question comes up a lot and the answer is almost always the same: yes, it will work if you use the Apple adapter, but at TB2 speeds and capabilities). So TB3 devices will only work at TB2 specifications however. USB-C is cloudy whether it works with the adapter. And it's not always clear from the product description whether a device is TB3 or USB-C, since the ad copy often seems to use the two interchangeably.

ETA: This device for instance claims to support either TB1 or TB2 with the adapter.

 
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Virtuoso

Socially Distant Member
Amazon has a TB2 Multidock (1 left!) for $626 - which does support Thunderbolt loop-through/daisy chaining for your monitor.

I don't see any claim in the ad copy or manual that the Multidock 10G supports daisy chaining - only that the second USB-C port can be used to split the drives between two workstations.

Check out this article for the differences between USB-C and TB3, particularly the section at the end on daisy chaining, which is applicable to your situation - https://www.imore.com/whats-difference-between-usb-c-and-thunderbolt

Thunderbolt ports and cables can be distinguished from USB-C by the lightning graphic.

 

JT

Senior Member
From the comments on various internet fora, it seems the adapter works both ways. (Read the comments and product descriptions on TB3 products on Amazon for instance. This question comes up a lot and the answer is almost always the same: yes, it will work if you use the Apple adapter, but at TB2 speeds and capabilities). So TB3 devices will only work at TB2 specifications however. USB-C is cloudy whether it works with the adapter. And it's not always clear from the product description whether a device is TB3 or USB-C, since the ad copy often seems to use the two interchangeably.

ETA: This device for instance claims to support either TB1 or TB2 with the adapter.

That's good to know. I'll give it a try and see what happens. Thanks.
 
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jbuhler

jbuhler

Senior Member
Amazon has a TB2 Multidock (1 left!) for $626 - which does support Thunderbolt loop-through/daisy chaining for your monitor.

I don't see any claim in the ad copy or manual that the Multidock 10G supports daisy chaining - only that the second USB-C port can be used to split the drives between two workstations.

Check out this article for the differences between USB-C and TB3, particularly the section at the end on daisy chaining, which is applicable to your situation - https://www.imore.com/whats-difference-between-usb-c-and-thunderbolt

Thunderbolt ports and cables can be distinguished from USB-C by the lightning graphic.
I agree with you about the lack of daisy chaining, and thank you so much for pointing this out. I assumed it had the same capability of the previous machine, in part, because I was confused about the extent to which USB-C and TB3 are interchangeable. Then too the manual for it on the BMD site has both of the multidocks in it without clearly distinguishing their capabilities. From reading around, it does seem like it might still work as a drive dock under TB2, but you are right it doesn't seem like it is designed to daisy chain.

$626 is the price now for the TB2 version, which is not horrible. When I purchased the other one earlier this week the price for the TB2 was $900! And it is very hard to find anyone selling the TB2 version besides Amazon. There is one very new business that claims to be selling them for half the price, but that seems too good...
 

Virtuoso

Socially Distant Member
I've had the Multidock 2 for a few years now and it has worked flawlessly, although the one negative is that it's not super fast. Even though it's a 20Gb/s TB2 device, each drive individually only does about 350MB/s and in a RAID it's limited by the SATA bus speed of around 600MB/s maximum.

Although the Multidock 10G is slower overall on paper, it now uses a separate SATA chip for each drive which may enable it to eke out the maximum 550MB/s from each SATA drive and give a faster result in a RAID (maybe around 1GB/s?). Can any owners of the Multidock 10G chip in with real world performance figures?

NB - This is still WAY slower than M.2 NVMe drives which can do up to 3500MB/s on PCIe 3 or 5000MB/s on PCIe 4.