So I received my Xonar Phoebus in the mail today and I disabled on board audio in BIOS, uninstalled Realtek drivers and plugged the card into my rig and in that order. On restart, the card isn't detected. Tried going to device manager and scanning for hardware with no luck. The sound card has power, indicated by the glowing logo and the lighting on the rear connectors.
Here's my config.
i5-3570K, Seasonic X-1050 Watt PSU, Asus Maximus V Formula mobo, 2x 7970 dual Crossfire in top two PCIe x16 slots, Running a clean install of Windows 8 64bit. The Xonar Phoebus is in the topmost PCIe x4 slot. However I've tried removing the GPU's and using the sound card in another PCIe x1 and x16 lane and the situation is still the same card is powered up but not detected. Have tried switching PSU cables also, no change.
Ok now I feel stupid, I installed the latest drivers and now everything seems to be in order. Though I enabled on board audio in BIOS and got an error during install that the card has insufficient power.
Seems strange though that Windows 8 wouldn't auto-detect hardware.