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USB 2.0 speeds on iMac M1 machines

It is great that the USB ports on new iMac theoretically support such fast speeds, but why are the throughputs of the SSD external drives on offer only operating at about USB 2.0 speeds? Is there an issue with the design of the M1 chip?

Posted on Jun 6, 2021 6:14 PM

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Posted on Jun 7, 2021 3:59 PM

External USB drives are can transfer up to speeds of 500MB/s on a good day. They are limited by the SATA interface that most external drives are connected to. The USB port is not the bottleneck.


Even so, that's not too bad so long as you're not using it as a boot drive for MacOS. They're cheap and do the job adequately.


If what you're looking for is speed that is as fast, or faster than your Mac's internal SSD, then what you're looking for is a Thunderbolt drive. These drives will give your extremely fast read/write speeds in the area of around 2.5GB/s.


They're not cheap, but when you want blazing fast speed, this is what you get.


https://appleinsider.com/articles/19/12/04/the-best-thunderbolt-3-ssd-and-hard-drives-for-your-macbook-pro-macbook-air-mac-mini-or-imac







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Question marked as Top-ranking reply

Jun 7, 2021 3:59 PM in response to speysider

External USB drives are can transfer up to speeds of 500MB/s on a good day. They are limited by the SATA interface that most external drives are connected to. The USB port is not the bottleneck.


Even so, that's not too bad so long as you're not using it as a boot drive for MacOS. They're cheap and do the job adequately.


If what you're looking for is speed that is as fast, or faster than your Mac's internal SSD, then what you're looking for is a Thunderbolt drive. These drives will give your extremely fast read/write speeds in the area of around 2.5GB/s.


They're not cheap, but when you want blazing fast speed, this is what you get.


https://appleinsider.com/articles/19/12/04/the-best-thunderbolt-3-ssd-and-hard-drives-for-your-macbook-pro-macbook-air-mac-mini-or-imac







Jun 6, 2021 7:17 PM in response to speysider

A USB 3.0 External SSD should run at the 5 Gb/s speed.


  1. Make sure that the drive is plugged directly into one of the iMac's USB-A port.
  2. If you have USB 2.0 devices on one port, try disconnecting them or moving to the other port.
  3. Get and use a high speed USB-C to USB 3.0 adapter and plug the external drive into that instead of USB-A.


For example, I have two USB 3.0 SSDs connected with two of the follow Philips USB-C to USB 3.0 adapters.

https://www.target.com/p/philips-usb-c-to-3-0-usb-a-female-adapter/-/A-79804275


Also other aftermarket USB-C to USB 3.0 adapters should also work just as well with the iMac.

https://www.amazon.com/Anker-Adapter-Transfer-Compatible-MacBook/dp/B078NKPGW9

Jun 6, 2021 6:33 PM in response to rkaufmann87

Sorry if I was unclear. The external SSD drives in the Apple Store such as the LaCie 1TB Mobile SSD High‑Performance External SSD USB-C USB 3.0, list throughputs up to 540MB/s, which is somewhat short of the 10GB/s speed of the port. I am wondering if getting a SSD with higher throretical throughput would be worth the money, or if this all the M1 can handle. Thanks for your response.

Jun 7, 2021 7:26 AM in response to speysider

Apple does not control what the third party manufacturers specifications are. If you want the fastest external SSD currently available then you need to buy one of these:


https://eshop.macsales.com/shop/owc-envoy-pro-ex-thunderbolt-3


The speeds are up to 2800mbs. They have other less expensive (slower) solutions too, if you cannot find one then what you are looking for does not exist.



USB 2.0 speeds on iMac M1 machines

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