Author Topic: Aggregate bandwidth of multiple USB devices on single controller  (Read 2547 times)

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Offline NiHaoMikeTopic starter

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Aggregate bandwidth of multiple USB devices on single controller
« on: February 17, 2024, 12:56:47 pm »
What total bandwidth would I get using multiple USB devices on a single controller?
Using USB 3.0 devices on a USB 3.1 controller, I will get a total of 10Gbps (minus the usual overhead) when using at least 2 devices. And that it also applies if I use a hub capable of 10Gbps, but a 5Gbps hub would bottleneck things.
Using USB 2.0 devices on a USB 3 controller, I will be limited to a total of 480 Mbps. And that using a USB 3 hub won't help as it doesn't translate the packets but just forwards them on.
Are my assumptions correct? Does it depend on the exact controller chipset being used?

The use case is connecting multiple USB cameras or video capture devices to a PC for machine vision.
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Offline Foxxz

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Re: Aggregate bandwidth of multiple USB devices on single controller
« Reply #1 on: February 17, 2024, 04:48:10 pm »
I believe you are correct. The USB2 interfaces continue using USB2 all the way through. I'm less sure about the USB3.0 on USB3.1 hubs but that sounds plausible.

One neat trick that I've seen used internally on laptops is that the designers will internally split the USB2 lanes from the USB3 lanes on a single port. They will use the USB2 lanes to run the keyboard/touchpad or other low speed devices and use the USB3 lanes for the internal webcam and card readers.

Just a nice way to make the most of your ports.

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