Same problem when downgraded to the generic windows drivers?
I found something like this, it helped a lot of people with the same isue. Maybe will help you too.
-> device Manager
-> Sound, video, and game controllers
-> right-clicked on the RealTek speaker item
-> chose "Update Driver software"
->click "browse my computer for driver software
->Let me pick from a list of device drivers on my computer
-> chose "high definition audio device" from the list and clicked
-> install it.