Like I said, those PCI cards suck up a lot of band width. The older PCI card for Alesis Adat Connect could not share any resources and had to be manually assigned to it's own IRQ. sharing with the USB hub shouldn't be a problem, but apparently it is! I have not had these IRq conflicts since I started using Intel Mobo's. My ASUS mobo has the same problems that you are facing. For reasons which I cannot explain, Intel mobo's architectures are more suitable for DAW applications. I think it may be that the other mobo manufacturers are designing boards with gamers in mind. Plug and Play is a great feature until you need to do manual assigning of IRQ's because of DAW applications. Is everything ok now?
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.