Separate all input jacks as independent input devices. Where is this option in the control panel, my line in input is seen as a microphone in windows and I have interference. This USB audio from realtek is a complete mess.
Get a dedicated soundcard. I bought soundblasterX AE-5 Plus coz I thought the onboard soundcard would sound better than my previous Sound Blaster Z card. The onboard Realtek sound is weak. Low volume. It's just bad.