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User profile for user: MarcelloM1973
MarcelloM1973 Author
User level: Level 1
26 points

Usb4 (TB3 latest) on M1 computers

I have the new Mac mini M1 and I am doing some tests. Among other things I noticed that my external UsbC SSD Raid that was giving me around 660mbit of data transfer on my iMac2017 (thunderbolt 3) is now only writing/reading at around 330mbit (that's half of that speed). I did some research and discovered that Usb4 (that is a particular protocol built on Thunderbolt 3) is not 100% retro-compatibile with "standard" Thunderbolt 3 / Usbc (that is 40gbit. /10gbit).


the paradox now is that my fastest (?) and news Mac will play slower my old disk.


I was wondering if other people have experienced this on other devices and if there are workarounds of some kind. Maybe it ends up just being the cable, maybe there are some dongle converters.. no idea.

Posted on Dec 29, 2020 9:34 AM

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User profile for user: barberlives123
barberlives123
User level: Community Specialist

Posted on Dec 31, 2020 1:40 PM

Hi MarcelloM1973,


Congratulations on your new Mac mini, and thanks for reaching out through Apple Support Communities for help with these unexpected slow speeds you're seeing. Rest assured, we'll get you pointed in the right direction.


As your external drive is a third-party device, we may refer to the manufacturer directly to inquire about a possible firmware update or workaround. First, let's see if we can determine that your Mac is otherwise working as expected.


Have you had an opportunity to disconnect any other connected peripheral devices or hubs before restarting your Mac and testing again? What's the current version of macOS installed on your computer? This can be found under Apple menu () > About this Mac.


As your Mac mini supports the latest USB 3.1 Gen 2 speed at up to 10 Gbps, you'll want to verify that the cable you're using is fully compatible with this specification.


We're here for you if you've got any questions.


Have a great day!

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User profile for user: barberlives123
barberlives123
User level: Community Specialist

Dec 31, 2020 1:40 PM in response to MarcelloM1973

Hi MarcelloM1973,


Congratulations on your new Mac mini, and thanks for reaching out through Apple Support Communities for help with these unexpected slow speeds you're seeing. Rest assured, we'll get you pointed in the right direction.


As your external drive is a third-party device, we may refer to the manufacturer directly to inquire about a possible firmware update or workaround. First, let's see if we can determine that your Mac is otherwise working as expected.


Have you had an opportunity to disconnect any other connected peripheral devices or hubs before restarting your Mac and testing again? What's the current version of macOS installed on your computer? This can be found under Apple menu () > About this Mac.


As your Mac mini supports the latest USB 3.1 Gen 2 speed at up to 10 Gbps, you'll want to verify that the cable you're using is fully compatible with this specification.


We're here for you if you've got any questions.


Have a great day!

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Usb4 (TB3 latest) on M1 computers

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