How can a Mac Pro read a thunderbolt 3 drive?

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How can a Mac Pro read a thunderbolt 3 drive?

I have a MacBook Pro 2018 and three Thunderbolt 3 external drives for various purposes. I have been surprised that I am unable to read the two bus powered TB3 drives using my Mac Pro 2013. I have the Apple TB3 (male) => TB2 (female) adapter, but even though it is advertised to run bidirectionally, it does not work with my two TB3 drives (Lacie model LRD0TU6 and TEKq 1Tb drive) which are bus powered. I have tried three different TB2 cables with the same result, which seems to eliminate the TB2 cable as the culprit. This adapter does allow me to operate my OWC TB3 Thunderbay 4 which has its separate power supply from the Mac Pro TB2 port. This suggests that the problem lies with the power bus in the two TB3 bus powered drives.

This problem is a real pain since I need the bus powered drives for their portability in the field, to move data between the MBPro and the Mac Pro. I would be able to tolerate the slightly slower speeds of the TB2 drives which can be read without difficulty on the MBPro using the adapter, but I cannot find any current portable TB2 drives on the market. Several AC powered TB2 drives remain, but the TB2 bus powered portable drives no longer seem to be available.

Any suggestions on how to either run the TB3 drives from a Mac Pro, or how to acquire a TB2 bus powered portable drive?

Thanks!

Posted on Nov 10, 2019 4:32 PM

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Answer 1

Best reply

William Mcclatchey1 Author

Level 1

19 points

Nov 12, 2019 6:43 AM in response to Grant Bennet-Alder

Thank you again for the responses.

As pointed out, the real rate limiting step for external hard drive speed is not typically the interconnect technology, but rather the underlying drive technology. I have found that TB2 going into a RAID drive array is much faster than any other rotating disc technology, including TB3 disc drives. No surprise And on the other hand, writing to a 5400rpm disc drive through a TB3 or USB 3.1 interface remains painfully slow.

Using USB 3.1 works, but at a significant speed penalty in comparison to TB3 with modern drive technologies. I find no TB2 fast portable drives for sale on Amazon or OWC except for the Lacie products which are snail like, while OWC continues to sell their AC powered TB2 RAID arrays. And the continuing performance confusion between USB-C and thunderbolt is particularly troublesome in trying to determine drive performance as well as cabling. There seem to be increasing external bus driven products with TB3 interfaces coming on the market, but they will not work with TB2 and the Apple adapter for lack of an adequate power bus.

So for the present I am relegated to using my AC powered TB2 RAID array for both the Mac Pro and the MacBook Pro, lugging it around if I need faster transfer of large amounts of data.

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Answer 2

Nov 10, 2019 5:31 PM in response to William Mcclatchey1

The Apple ThunderBolt-3 <--> Thunderbolt-2 adapter does not provide:

• any usable display interface except genuine ThunderBolt

• Power across the interface for Bus-powered drives (in either direction).

• support for drives on ThunderBolt-2 Macs when using MacOS OLDER that 10.13 Sierra

About the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter - Apple Support

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Answer 3

Kappy

Level 10

361,741 points

Nov 10, 2019 5:04 PM in response to William Mcclatchey1

True TB3 disks require TB3 ports capable of 40GBps transfer rates. The ports will not work if you have added them via a third-party card.

I have a couple of true TB4 disks that will not work on my iMac unless connected to one of rear TB3 ports on the computer. I have a TB3 dock in use but the disks won't work. The system produces an alert that says the external disk must be connected directly to the computer. They work fine when so connected.

I'm not sure why this is the case, but I suggest you ask LaCie tech support. Their engineers probably know.

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Answer 4

Nov 10, 2019 7:16 PM in response to Grant Bennet-Alder

Thanks for the responses.

I understand, and had deduced the limitations of the apple thunderbolt 3 <=> Thunderbolt 2 adapter.

So I have to ask the question again, if I have a TB3 MacBook Pro and a TB2 Mac Pro, are there any portable drives out there that will work on both machines and that will exceed USB 3.0 speeds with adapters?

Has Apple really dead ended high speed communications between two of its high end machines?

Thanks!

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Answer 5

Kappy

Level 10

361,741 points

Nov 10, 2019 8:53 PM in response to William Mcclatchey1

I'm afraid your 2013 MP has been replaced as Apple's high-end box. It does support TB2 for which there are plenty of portable drives that will work. You can find what you want at OWC and Amazon. However, they use a different connector than TB3. The latter uses "USB-C" while the former uses the older TB2 connecter. TB2 cables are still available at Amazon and OWC. However, the TB3 drives may be reliably connected to the MP via USB 3.0/3.1 Type A (standard USB). That port is capable of up to 10Gbps. Not as fast as TB3 but quite usable. I have a lot of SATA SSDs I run off USB ports. They are quite fast but not nearly as fast as TB3. You can use TB3 enclosures (expensive) to get 40Gbps on your MBP, but they would not work on the MP. You would need to use enclosures that work on a TB3 port but can be used on a USB 3.0 port with a cable that has a USB-C connecter on one end and the USB connecter on the other end or you can use the standard TB3 cable and a USB-C female to USB 3.0 male plug on the other end of the adapter.

I have two purely TB3 external SSDs in very expensive TB3 enclosures ($159 each) that will only work if directly connected to the TB3 ports on my 2019 iMac. I also have a CalDigit TS3 TB3 dock (around $280) that has one port in and one port out at TB3 speed. Must be used only with TB3 40Gbps rated cable (and can't use a power cable.) I've been down the same road as you. TB3 speed is expensive. You pay a lot for the speed. Have to ask yourself if 40 is worth the money or just stick to 10Gbps which is much less expensive.

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Answer 6

Nov 11, 2019 7:37 AM in response to Kappy

This is not a disaster. If the interface speed falls back to USB 3.1, at 'only' 10 G bits/sec, that is still a theoretical 1250 M Bytes/sec. That number is much faster than commodity SSD drives, and very comparable to a lot of fast SSD drives, so would not slow those drives substantially. (I think of fast SSD drives as marketing-speak 1500, real world closer to 1250.)

But Faster drives are becoming available. And for those you would not see the faster speeds on this slower interface.

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Answer 7

Kappy

Level 10

361,741 points

Nov 10, 2019 5:58 PM in response to Grant Bennet-Alder

Thanks for adding that, Grant. I forgot to.

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How can a Mac Pro read a thunderbolt 3 drive?

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