Audio hardware requirements

If running plex server and client on same windows server, and sending the audio to a receiver via hdmi, what are the audio hardware requirements (sound card etc) of the windows server in order to play multi channel hi-res lossless audio such as flac?

If using pass-through, is there any audio hardware requirements from the server side given that the receiver will do the decoding?

If using direct pcm, given that the windows server will not actually play the sound, is there any audio hardware requirements, or is is just cpu which will do all the work?

Thanks in advance.

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