Usb Hub for Thunderbolt 3 / Type C

[DaveTeu]

I'm looking at product similar to the images below. I see many different hubs like this mention speed of 5Gbbps

The interface type is USB Type-C.

May I ask if I plug such usb hub product into my Thunderbolt 3 port (I am on a iMac 2020 27"),

1) will each individual port give me the maximum 5gbps speed if I concurrently plugin 3 external hard drives to the hub? Or will they be divided? How does it work?

2) What If I plugin a NVME Thunderbolt 3 (40gbps) external drive in one of those port, what will be the theoretical speed I will be getting from each of those ports? Will it be able to reach 40Gbps?

 

[velocityg4]

1. The interface to the computer is 5 Gbps. Which means that's the aggregate speed of all devices. Any device can work at a full 5 Gbps. But if multiple devices are working concurrently. That speed will be split between them based on their current needs.

2. It won't work. A Thunderbolt device must be directly connected to a Thunderbolt port. This can be on the computer, on a Thunderbolt hub, a daisy chained Thunderbolt device, &c. The hub is USB C not Thunderbolt. It cannot pass through a Thunderbolt connection.

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Basically, if you want or ever think you'll want Thunderbolt from a hub. You'll need to pay the piper and buy a Thunderbolt 3 hub.

 

[joevt]

1) will each individual port give me the maximum 5gbps speed if I concurrently plugin 3 external hard drives to the hub? Or will they be divided? How does it work?

The max of each port will be USB 5 Gbps. The max total will be USB 5 Gbps.
USB 5 Gbps = 4 Gbps of data = ≈460 MB/s (sequential read/write).

For USB 3.0, there are separate lines for receiving and transmitting. So you could send 460 MB/s to one device while reading 460 MB/s from another device.

If you connect 3 drives to the hub, you can use ATTO Disk Benchmark.app to send data to all drives at the same time. It will show the total limit is ≈460 MB/s.

2) What If I plugin a NVME Thunderbolt 3 (40gbps) external drive in one of those port, what will be the theoretical speed I will be getting from each of those ports? Will it be able to reach 40Gbps?

40 Gbps of data is not possible. The max data is around 23 Gbps (≈2800 MB/s) from a Thunderbolt port. Basically, the amount of data you can send over Thunderbolt is 2800 MB/s or whatever is not used by DisplayPort data. For example, an Apple Pro Display XDR connected via Thunderbolt to a Mac that doesn't support DSC uses ≈38 Gbps of bandwidth leaving very little for data (at least for transmit - DisplayPort does not use much receive bandwidth).

Of course, the USB Hub doesn't have a Thunderbolt port. I am talking about the Thunderbolt port of the MacBook Pro.

An NVMe Thunderbolt 3 drive will not work connected to a USB hub - unless it's something like the ACASIS USB4.0 enclosure which can do either USB or Thunderbolt - it's not really a USB4.0 device - it can't do full Thunderbolt bandwidth connected to a USB4 host that doesn't support Thunderbolt but I don't think there are any USB4 hosts that don't support Thunderbolt yet.[/QUOTE][/QUOTE]