It sounds like you are using ActiveX to control Excel using the Example VIs as provided with LabVIEW. If this the case, please see this thread from one week ago: http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000F67B0000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0
If you are trying to write to a text file, try using the "Write to Spreadsheet" VI and wire your data as a single 2D array. This will write your data as a single disk access. My machine wrote 8000x5 DBL in 125ms. Michael Munroe Certified LabVIEW Developer www.abcdefirm.com
