Well, more information is needed in order to provide the adequate advice.
About Multithreading, check the following information from ni.com:
Application Note:
Using LabVIEW to Create Multithreaded Applications for Maximum Performance and Reliability
http://digital.ni.com/appnotes.nsf/b0be082ea11554328625648f006a132a/99dbde3436c215208625658a00633640?OpenDocument
KnowledgeBase:
Is multithreaded LabVIEW real-time?
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/277303856cf47ca3862565bc006c002c?OpenDocument
Good luck!
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