USBMan has posted an USB 2.0 PCI card list
USB 2.0 cards require 2 IRQs. 1 IRQ supports USB 1.1 and the other the Enhanced (USB 2.0) controller.Read more
Installing the USB 2.0 card in the slot that shares an IRQ with the onboard USB 1.1 Host controller usually produces the best result. Consult your motherboard manual or online guide to determine which PCI slot shares its IRQ with onboard USB.
