Matt,
Is that true? In looking at the NI catalog, a PCI-6052E card is a 16-bit, 333 kS/s card. Therefore, since the maximum multiplexing speed of the SCXI is also 333 kS/s, the max sampling rate should be 333 kS/s for one channel, I thought.
Since the A/D conversion is on the PCI card, I would assume that it being a 12-bit or 16-bit card doesn't matter. It's the speed of the card that does.
Mark