GSX doesn't have any control over the actual audio device and doesn't know anything about its drivers.
It uses the standard OpenAL library, which sits on top of DirectX, that sits on top of the actual audio drivers.
If an audio device works correctly with OpenAL, it will work in GSX but if it doesn't, it won't, and there's just nothing we can do about it, since nothing in the GSX code has any knowledge of how any particular audio device really works. From GSX point of view, it's all just OpenAL.
Sometimes, OpenAL works better by using the default audio drivers that come with Windows. Sometimes, it works better by installing the audio drivers supplied by the manufacturer. If the audio is integrated on the mainboard, they are usually found on the mainboard manufacturer website. There's no rule to know which one might work best, because it depends on the hardware, the only thing is trying.
The Realtek audio is very common, and of course it works fine with GSX, that's what I'm using right now, and the driver I have installed is version 6.0.8158, made by Realtek, so it's not Windows default, but it's installed separately, from the mainboard manufacturer site ( ASUS in my case )
