Sonar 7 and Storm drum users-Multi core concern!

I just need you all to either try something oir fill me in on what I have discovered. If I load 2 or more instances of a project that has recorded data with storm with Multi processing engine ticked in the audio-advanced tab, and play back the project, it seems that storm drum causes Sonar 7 to cause bad blip sounds then eventually no sound resulting in lock up of sonars input meters making storm drum usless. Now if I untick multi processing engine and play back the audio all works as expected. Any comments please?.