I may have missed it, but has anybody suggested you take that USB interface to someone else's house and install it on another computer? Or a second computer of your own (but I don't think you have 2 if I recall from past conversations.) just to take your computer out of the equation? Also if it is set up as your system sound card you should be able to play CDs and streaming internet radio through it. Eliminate as much as possible.

The ONLY reason I would doubt the BIOS is the definition of the term itself. Basic Input Output System. His system component (USB port) is not failing. Also given that 17,936 billion computers (I statistic I made up for this post) have outdated BIOS and don't have this issue I would question the BIOS as the issue. Using the USB bus and not the board's data bus leads me to believe that BIOS is not the problem.

Also, to whoever suggested the USB data bus has been overtaxed, unless he is playing with RB, moving the mouse, printing, dumping photos from a camera, etc... he isn't using all the USB devices at once. They don't consume bandwidth just being plugged in, only when there is I/O happening. And just for an example, one of my computers has a webcam, a printer, a USB turntable, a CD storage jukebox, a PID, a iPod Shuttle charger and 2 thumb drives plugged into the USB ports (with a hub obviously) RIGHT NOW and there is no performance degradation at all. And that is on an older Dell without the horsepower Richard has.

I would also doubt it is the pwoer supply because of how the USB draws power. It comes from the PSU connection to the mobo, not from one of the power rails. And again, not all of the USB ports are drawing until used, and this is a new computer with like a large power supply. If the power supply were bad, again given that the power is coming through the mail connector to the motherboard, he would likely be seeing a lot of other problems. With the drives each being on their own 5v power rail, they could be fine and not indicate a PSU issue. Particularly with SATA conenctions....
Step one for me would have been try it on another computer.