You need an analog connection for these.
If you are an audiophile using an external DAC to drive high-impedance headphones, you might use the Digital Output (Optical) to connect it. realtek digital output better
If you have a high-quality external DAC, amplifier, or home theater receiver, use the digital output. External audio equipment almost always features superior digital-to-analog conversion compared to the mass-produced chips on a computer motherboard. 2. You Are Experiencing Hardware Interference You need an analog connection for these
Your motherboard's built-in Realtek sound card processes the digital file. or home theater receiver
If you connect your PC to a dedicated home theater receiver or a high-fidelity desktop DAC, the external device will always have superior conversion chips compared to your motherboard.