I have a Xonar Phoebus for a little over one year now and it always worked perfectly.
Couple of days ago i migrated to windows 8.1 from windows 8. The card was working fine but yesterday it decided to completely vanish from every place, including the device manager.
I downloaded the 8.1 x64 drivers but it says during the install that the card "doesn't exist".
I have all lights on on the card (the pink asus name and the red & green lights on the back).
I tried moving the card to another PCI-E port but no luck.
I'd have tested it on another computer but none of these have a free 6 pin power slot, unfortunately (modular power supply and international relocation made the extra cables vanish).
Are you aware of issued linked with the card vanishing for 8.1, even if u have official drivers for it ?