I think that's the most logical choice though.The problem was apparently not with the DAC cable. I finally gathered my wits and tested the AOC-STGN-i2S in my main desktop and it worked just fine with all of my DAC cables no matter what the encoding. So the problem is definitely with running it in the M90q Gen 3.
I did try all of the following in various combinations:
Nothing helped and now I am at the end of my wits. Perhaps I should purchase the x4 riser to try that out, but I'm not particularly keen on spending even more money on this.
- Disabled network boot for the NIC in the BIOS
- Changed PCIe settings from "Auto" to "Gen 3" and then later "Gen 2"
- Updated the M90q Gen 3 BIOS to the latest version M4GKT22A (The upgrade froze at the "Backup BIOS" step, but the M90q was able to recover, when I power-cycled it after waiting for 9 hours.)