this is for version 2 but basicly the same info...
ASIO is a standardized way of describing the communication between audio software and a piece of audio hardware. It enables audio hardware manufacturers to write optimized drivers for their hardware that bypass the potentially high latency operating system mechanism for supporting audio hardware. This OS support is also often only stereo because of its multimedia background. For a user, the knowledge that an ASIO driver exists for a particular piece of hardware, is a sign that there will be a performance boost, compared with the same audio card configured to use the Operating System's own mechanism, and often an accompanying latency reduction, shown by reduced monitoring delays.
