I have an AMD Radeon HD 6870
The drivers are all up to date, but windows seems to think the device is stereo only. On the box, which I still have, it says it supports up to 7.1 surround sound, and including 5.1, but nothing I can find in the catalyst control center or Windows 10 seems to have any settings to enable 5.1. Among other issues, it also states that it supports audio over minidisplay port, which it wont do for some reason. The cables I purchase advertised audio too, but windows pops up a message any time I use them saying "display port does not support audio, you will need a separate audio cable". Mostly I just use the HDMI port anyway, but my key issue is that I want my 5.1 surround sound but cant seem to enable it anywhere in the 5 or so windows audio settings menus or the catalyst control center.