Long story short I am trying to get my basement setup to run 5.1 surround sound audio from a PC to a receiver for movies, games, etc.
I have a Yamaha RX-V361 receiver with speakers connected to it in a 5.1 configuration. I have an older desktop I was going to use for this purpose, my custom build from 2013(ish) which has an FX-8120, in a GA-990FXA-UD3 mobo which has optical audio out. This should be capable of outputting dolby digital or DTS 5.1 audio signals out. In fact I know it does, because when I test these encode formats in the sound settings I can hear each speaker independently playing sound. (see next picture to see where I am testing the sound).
It would seem that when I updated this computer to win 10 from win 7 the Realtek drivers associated with the mobo decided to just no longer support 5.1 sound and all it will do is 2.0, which doesn’t even make any since because I can still go into the sound settings and test a 5.1 signal and hear that is works and then there is no option to use that signal as a default, only 2.0 options (see next picture).
There isn't any modern info on the LTT youtube about audio or sound setups for computers in living room configurations. So I came here to ask: Am I screwed? Do I buy a $120+ PCI sound card just to get 5.1 optical audio out, or is there a different solution here that would involve a different receiver. I'm very lost on this issue and would appreciate any help anyone could give.
P.S. I did also try getting different drivers per this microsoft suggestion on the problem but had absolutely no luck with that. https://answers.microsoft.com/en-us/windows/forum/all/51-optical-not-working-in-windows-10-1809/a9026823-9ce4-458e-a7e1-11047c863c33