i have this sound-card and i also want to know the answer to this. I assume that the 32 bit is restricted to internal processing and then get down sampled to 24 bit in the sound card, but i have just asked asus themselves and should get an answer within 48 hours. And when i do i will post the answer here for anyone else who wants/needs to know, unlike the original poster who boasted he had the answer but thought he would keep that to himself.