The Xonar D2X sound card from ASUS is their top line sound card. Based
of the design of the D2, the D2X is out with the old and in with the
new. ASUS has updated some of the components on the board, and changed
the interface. The AV200 HD audio processor is still there, which means
that this card supports most every audio acronym under the sun. However
the D2X uses the PCI Express bus, which is a huge differentiation from
the many other PCI based cards on the market.

http://www.futurelooks.com/asus-xona...d-card-review/