I just had a mouse fob in the USB 3 port. That is when it complained about using too much power. Odd because the fob is just a fob--the power is in the mouse in the form of 2 AA batteries.
It is okay though. Once I get the HDD issues figured out, I will install OS X and OS 9 on the drive and just use the USB 3 card with OS X.
I had caught a 2 for 1 sale at a local computer shop, so I took advantage of it. Got both cards--one in the 08 Mac Pro and thought it would be cool to expand the QS USB capability without dragging out my USB 2 powered hub. But I know I am asking too much of OS9 to run it. Still, I had hope, and that is something!