From the MOTU website
http://www.motu.com/products/avb/16a
State-of-the-art latency performance
Every digital audio workflow has some latency. The only question is, how much? In the case of the 16A, the answer is, not much at all. In the 1248, latency is measured in a handful of samples, from the time an audio signal first goes digital to its arrival somewhere else (to an output, the mixer, or the computer). By keeping latency this low in the hardware, the 16A helps minimize latency introduced by your host software. Over Thunderbolt, round trip host latency is an impressive
1.4 ms, from analog in, through the host, to analog out (@ 96 kHz with a 32-sample host buffer)