Should I use z370-h onboard audio 'SupremeFX' or External sound card Asus Xonar u7 Mk2 With DT770

Apr 24, 2018
So I have Beyerdynamic DT770 Pro 80 ohm version and I use an external sound card ASUS Xonar U7 MkII. However, I purchased new motherboard Asus z370-h Gaming which also has quite a good onboard audio.
For comparison, The External sound card has SNR 114dB and supports 32-150 Ohm headphones and the motherboards onboard audio device SupremeFX has 113dB SNR and supports 32-600 Ohm headphones.
So the question is which one should I be using in terms of music clarity and volume it can produce?
I'm also considering to purchase sometime in future the 250 ohm version of the DT770 so that should be taken into the consideration.
Sorry for my bad English and thank you in advance for answering!
Since you have both in hand(in possession) why not just try them both out? You can disable the onboard if you like the U7 but IMHO, I think you'd have a better experience with the onboard.