speed up excel insert

i am inserting dynamic columns into excel and it is taking about .4 seconds / insert for 200 headers so its amost 1 full min to insert the headers.
short data goes much faster and the headers are long text each.
is there perhaps a faster way to insert the full headers in 1 shot?

With oExcel.Worksheets("Data")
 For i As Integer = 0 To arM.Count - 1
   Dim oMToShow As M = arM(i)
   .cells(iRowMName, oMToShow.MNumberColumn).value = oMToShow.MLabel
 Next

like is there a way to make it an array and insert it into a range or create a row object and insert the row object all at once?

BTW i want to "update" and not strickly "insert" (add a new row)