Asrock Z77 Extreme 3, latest BIOS
i7 3770
Windows 8.1 x64
Secure boot, UEFI mode, CSM disabled (using UEFI GOP mode due to dedicated R9 280X with fully UEFI GOP compatible BIOS)
All latest drivers
If I disable CSM - my TV is not appearing on my HDMI audio playback devices. When I enable it - everything is OK.
If I recall - this wasn't happening on Windows 7.
I see this (same issue) was already been mentioned:
HD4000 no HMDI Audio with UEFI GOP
Any chance of fixing this issue?