Is USB sound cards better than internal in terms of noise/interference?

Question

When I bought my last sound card (for hifi-headphones) the store recommended me to buy a USB soundcard/DAC since internal cards are subject to electrical interference from everything else in the chassis.

I've googled a lot to verify that claim but get really mixed results when reading.

Has this been debunked or verified in some way? Or is it just a matter of opinion?

Edit:

I'm not talking about comparing the built-in sound card with an external, but comparing two cards of equal quality. Will the internal card be subject to more interference from the rest of the electronics in the chassis? Or is it so minimal that no one can tell the difference?

Answer 1

If you are happy with the inbuilt sound card, by all means keep on using that.

External sound cards are generally much better if you want to record from a microphone. If all you do is listen on headphones, the difference is much smaller.

Some external sound card, the expensive ones generally, might have better headphone amplifiers allowing you to drive the headphones "better", that is with less distorsion and with higher power from the amplifier. For some headphones this may be a quite noticable difference, for many you might not notice much. As for noise and interference, unless you hear some now it will not be different -- none is none regardless.

When you run external "studio monitor" speakers with balanced inputs an external sound card with balanced outputs may make a large difference as it protects agains mains hum. But again, if it works anyway...