Tip #1132: Not All Thunderbolt Cables are High Speed

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Tip #1132: Not All Thunderbolt Cables are High Speed

Larry Jordan – LarryJordan.com

Thunderbolt 3 cables are not the same – and many slow your data down.

(Image courtesy of Intel.)

Topic $TipTopic

One of the most interesting things I learned recently is that not all Thunderbolt cables deliver the same performance. Even Apple’s cables have significant limitations.

I discovered this in an interview with Larry O’Connor, CEO of OWC, a company that specializes in Thunderbolt peripherals.

Here is an excerpt from our interview:

Currently, USB-C cables don’t support Thunderbolt and most don’t even support full USB 10 Gb/s data speeds. For example, the cable that Apple includes with its laptops only carries USB data at USB-2 480 Mb/s speed, not even USB-3 5 Gb/s!

Also, today, Thunderbolt 3 passive cables only provide 40 Gb/s at lengths up to 0.8 M and 20 Gb/s at lengths longer than 1 meter. (I should note that all passive Thunderbolt cables do support full USB-3.2 10 Gb/s speeds)

Sigh… It gets worse. Thunderbolt 3 cables 1 meter or longer are active, which means they have electronics in them to provide the full 40 Gb/s speed. But, while delivering Thunderbolt 40 Gb/s they only deliver USB-2 480 Mb/s speed (that’s a max of 60 MB/s of total data throughput vs. about 600 MB/s with USB-3 5 Gb/s or about 1,200 MB/s with USB-3.2 10 Gb/s)

So, if you are not getting the speed you expect from a Thunderbolt device, or a device connected using a Thunderbolt cable, the first place to look is the cable itself.

Read the full interview here – it is well worth your time.

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2 replies
  1. John Roloff
    John Roloff says:

    Thanks for this information. Please include in an update where to find and distinguish the faster Thunderbolt cables from the slower besides length. Is there a part number or other signifier in order to know one is ordering the fastest? Will this be the same issue with Thunderbolt adaptors and Thunderbolt 4 cables? Thank you.

    • Larry Jordan
      Larry Jordan says:


      From what I’ve learned so far, there’s no easy way to distinguish the faster cables. Unless the cable is certified for Thunderbolt 4. Theoretically, Thunderbolt 4 certification for ANY device means it will run at full speed.



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