Moore Zhang wrote: > > > I happened to find that when I plug in my USB 1.1 audio device in the > USB 3.0 controller port, there will be noisy when playing music with > WMP. But if plug in USB 1.1 or 2.0 controller port, always fine. I’m > prepared to analyze and debug the driver code now, but before that > does any guy in this list has similar experience of this issue? Should > AVStream audio driver make special process for USB 3.0? > Prior to Windows 8, the world of USB 3.0 is a jungle, because Microsoft does not support it. When you use a USB 3 host controller in Windows 7, you are using a driver stack provided by the host controller manufacturer. No one knows what rules they followed, or what quality control they used. There SHOULD NOT be any difference for a USB 2 device plugged in to a USB 3 port, but I know some of my web cameras do not operate in some USB 3 ports, and I have no explanation for it. I suggest you try your device in a Windows 8 system with USB 3 and see if it behaves correctly. -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc.