I agree with Markoneswift, if you’re using WASAPI then in theory, your digital audio signal is going bit perfect and unaffected to your receiver through HDMI no matter what card you have. All the processing is in receiver. The reason HDMI sounds better (is better) than optical is that optical can either send true hi res to stereo speakers, or at best, Dolby Digital (24/48) to 5.1 but not hires to 5.1. HDMI can send your highest sample rates (32/192 , more?) discretely to what, 10 channels? Big leap in resolution and dynamics.
Reminds me of another post I read recently where someone said he had to shut all the processing off on his Blu-ray player to get Dolby Digital to work, lol. Dolby Digital was 1990. If you’re shutting off DTS Master audio to go to Dolby Digital, go get an ear exam, lol. Optical or coaxial digital is ok for stereo, but way inadequate for any modern surround system worth its salt. HDMI is the only real way to feed a surround processor. If you have noise issues due to components grounding, the answer is to go to a power supply like a Monster Power unit. I have a few, they work, and protect your gear. No noise ever, and everything in my system is plugged into one supply, TV, laptop, all audio, everything. Oh, and they’re all stacked in super close proximity and cables not so neat, but sound is clean and pure. Clean power and good source material, decent components, all more important than fancy cables and wiring. Room calibration is a good thing too, IMHO. Let the receiver do it’s job and manage the sound, just use HDMI and WASAPI or ASIO drivers to insure an unaffected source signal.
My current internal debate is the Sony X700 or X800 Blu-ray player. I just landed a leftover LG C6 Oled (55”) for the best 3D ever produced on a TV, and now I need a 4K player to go with. Thing is, the TV does Dolby Vision which is gorgeous. The problem is that, of the 2 players, the 700 has Dolby Vision support, where the 800 lacks Dolby but plays DVDA. Now, generally all my music is on a hard drive, and I can read DVDA on a PC so a stand alone machine no super important, but I did want a universal disc player. I’m leaning toward the Dolby Vision since I have other DVDA options, but WTF Sony? Put Dolby on the 800!