My question is about USB 2.0 devices on a USB 3.0 controller. I have four webcams coming into one USB 3.0 controller. We’ve had issues in the past with power, so we got an externally powered USB 2.0 hub, which seemed to do OK for three cameras. When the forth one comes in, we run into data bandwidth issues.
Now, since it’s a USB 2.0 hub, if we went and got a USB 3.0 hub, I assume there would be a boost in bandwidth, but would it matter if the webcams are still 2.0?
Also, does it matter on the type of USB extension cable that we’re using? It's just a standard A-male to A-Female connection, but is there a difference between USB 2.0 and USB 3.0 cables (aside from connection interface) or is it just the ports?
Best Answer
Depends on the HUB IC. If there is only a Single Transaction Translator, then the USB 2.0 (Or Worse 1.1) devices share bandwidth between the hub and the host, only one at a time. If the HUB IC has a Multiple Transaction Translator, the bandwidth should be multiplexed, so that all the information goes over a single xHCI channel.