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At work, I want to plug all my USB devices into a single USB hub so I only need to plug one USB cable, external display, and the power cable into my laptop. I have some USB 3.0 devices and some slower USB 2.0/1.1 devices.

I'm aware that all the devices on a single USB Root Hub share the same bandwidth, but I'm curious whether plugging an older device into a hub causes the entire hub to fall back to a compatibility mode.

If I plug the slower devices into my USB 3.0 hub, will that hub and all its connected devices slow down to USB 2.0 speeds, or will the USB 3.0 devices continue to run at USB 3.0 speeds?

For example, suppose I have an USB 3.0 gigabit network adapter and an USB 2.0 keyboard. If I plug the keyboard into the same USB 3.0 hub that the network adapter is plugged into, will the network adapter's maximum theoretical throughput instantly drop to 480 Mbps or slower (USB 2.0's maximum throughput)?

rob
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2 Answers2

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Short answer: No.

Long answer:

I stumbled across the answer to my question in a comment to an answer for a seemingly unrelated question. It turns out USB 2.0 and USB 3.0 are physically segregated in the wiring, so plugging USB 2.0 devices into an USB 3.0 hub won't affect the performance of USB 3.0 devices in the way that I was wondering.

Community
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rob
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No.

Here is how to imagine speed in wires.

Think of it like a tunnel that transfers water.

Assume a big tunnel is split evenly into several similarly-sized tunnels (HUB). Next, you connect your 2.0 device (which is a smaller tunnel comparing to 3.0) to the hub.

What happens? Do the other tunnels get smaller? No, they do not. Your 2.0 device uses as much speed as it can.

This analogy really helped me to understand network problems.

Dennis Wurster
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UltraDEVV
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