No audio with VT-d

Hi, I recently built myself a new system with the Gigabyte X79-UD3 + i7-3930k. When I enable VT-d in BIOS I don't get audio anymore in Windows 8 x64 UEFI. I did get audio when I was in legacy BIOS mode before the recent OS reinstall. VMWare guests DO get audio in UEFI mode, the host doesn't  . In the Playback Devices tab I can only see HDMI audio when plugged in to a monitor with speakers or a tv. Without VT-d i can use the realtek audio. I have installed realtek amd hdmi audio after installing Catalyst 13.1/13.2 beta(Sapphire HD7970). I'm on F11 BIOS, any ideas? I would prefer not to reboot when i want to switch between audio from host and guest