Labview RT works with three different types of targets:
-RT series DAQ (Traditional Data Acquisition board with a processor board attached to it. Connects on a PCI slot of your machine)
-Field Point:Distributed modules for Data Acquisition
-PXI factor: Systems where you need a chassis and a controller then you can start filling the slots with the type of hardware that you need for your application.
Then using a traditional SoundBlaster Card to acquire data under Labview RT is not going to be possible at the moment.
Blasioz Valenzuela
National Instruments
Labview RT Applications Eng.
*Note: Did you try the same application in a faster machine, this can improve the performance and hopefully not miss data.