On a russian site (thx to user Kirych___83 for the tip) i found a solution to get your soundcard back to work, if she dont get recognize at cold boot or for any other reasons. It's only for people who are out of warranty and don't care if it breaks.
I did it on my Strix RAID DLX 4 days ago and my Soundcard works again.. no problems anymore. At first I had extreme doubts that it would work and that it would be so easy.
For ASUS Strix Soar and ASUS Strix RAID PRO: (the two cards are almost identical) Remove the two ceramic capacitors marked in red on the picture.
Here the original PCB pictures for the Strix Soar and RAID PRO Strix Soar
Strix RAID PRO
For ASUS Strix RAID DLX: Remove this one ceramic capacitors marked in red on the picture.
Here the original PCB picture for the Strix RAID DLX
Do it on your own risk and only if you dont have warranty anymore. I only tested it on the ASUS Strix RAID DLX.