PS: I have been talking with Ross about this and he sort of agrees, he is sitting in my office.
Oh well, please tell him that the Coreaudio implementation does not try to set the sample rate, it just accepts the one presented by the audio card. (Which results in 96 kHz in my case, with resampling by Coreaudio from 44,1 kHz @ 8 channels results in about 35% cpu)
best greetings, Thomas