Yeah, a pci-card would need drivers. The mackieOS only have drivers for the hardware it came with.
Regarding noise - I ended up getting an opt-24 card, which let me get rid of the card cage internally.
Then I moved the small pcb above the cpu to where the card cage was before (using a self-made plate on the back).
Then I could install a large heatsink and fan on the cpu. Right now it's using an 80mm noctua fan. Very quiet.
I also installed a new psu. So it almost silent. And a bit hot inside, since the air moving through is less than before....