*Update - problem happens as soon as I use MSI LiveUpdate 6 to install audio drivers - problem seem to be solved after disabling onboard HD audio settings in the BIOS iteself - will keep updating if problem persists.
Make sure you also install latest motherboard BIOS.
And while using MSI Live update, do you have .Net framework 4.0 installed?
MSI LIVE UPDATE says:
1. .net framework 4.0 is required.
2. Antivirus Software need to be disabled to prevent conflict when using Live update utility.
Also if you have MSI Afterburner\MSI gaming app installed, uninstall them and check if it works. Usually on the Asus side, their utility apps make the whole PC to crash\BSOD\Black, Gray Screen... (happened to me with Asus Smart Doctor in the past, Asus GPU Tweak I, and happened to my RX480 Strix with GPU Tweak II). After latest Asus update for example the problem with GPU Tweak II got fixed for their Asus Strix RX480.
If you can use Msi Live Update 6 utility after disabling HD audio on the BIOS, then update the GPU bios to the latest version, then uninstall the utility and turn HD audio back on and install latest audio driver from the audio chip manufacturer (not from the motherboard site).
However if you use other external\internal Sound Card, then let HD audio disabled. You can also disable everything you dont use on your motherboard, like 1394... (I always disable everything in my PC's that I dont use, like Internal audio since I have a PCI-E soundcard, 1394, 2nd lan slot, Sata controller ports that I dont use...).