DH29, on 8 series motherboards, the limitation of end points is 96 as I mentioned it before.
Bear in mind that each USB device can support multiple end points and how many end points can support vary by device. Once it reaches to the max endpoints, you will get a pop-message, the limitation is not based on number of devices supported but the end points.
So for example, it’s possible that a customer connects only 15 USB devices and then he will get that pop up messages. Everything is going to depends on how many end points the USB devices uses.