But be aware, there is a bug using multiple cards in OSX 10.8 and higher.
The bug results in the card order beeing swapped at random when booting the computer.
So you expect to send audio out on card 1 but is sending to card two.
Same problem exists with both SSL and RME Madi cards so I suspect it will happen with multiple AIO cards as well.
According to SSL it's a OSX bug that Apple has to fix.
If you can run 10.7.x it all works as it should
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Dubstage, foley, sound editing, picture department.