M-series devices can be used with NI-DAQmx only. The delay is the time to load the dll's that implement NI-DAQmx. You could call some DAQmx function (any function will cause it to load and incur the delay) when you start up your application. That way you get the delay out of the way at a time when it doesn't matter.
John Weeks
WaveMetrics, Inc.
Phone (503) 620-3001
Fax (503) 620-6754
www.wavemetrics.com