Writing a large VBA array to the worksheet in a single operation, rather than cell by cell, can result in a huge improvement of the speed of many macros.  The basic technique was described here.  I recently wanted to modify this technique to write a number of arrays from a loop into adjacent ranges on the same sheet, then adjust the range name to cover all the arrays, so they could be cleared in one operation.  This is the code I came up with:

' Clear all old data
Range("DfileRes").ClearContents
' Reset column offset and maximum number of rows counters, and number of columns per array
DatOff = 0
Maxrows = 0
NumCols = 11

For i = 1 to NumOut
' Fill array "Stressa"
' ...
' Get size of output array; Numrows and reset Maxrows if necessary
' ...
If Numrows > Maxrows then Maxrows = Numrows

' Write array to spreadsheet
Range("DfileRes").Offset(0, DatOff).Resize(NumRows, NumCols).Value = Stressa

' Recalculate column offset value, "DatOff"
DatOff = DatOff + NumCols + 1  ' 1 blank column inserted between each output array

Next i

' Resize output range to cover all data
Range("DfileRes").Resize(Maxrows, DatOff).Name = "DfileRes"

The line that does all the work is:

• Range(“DfileRes”).Offset(0, DatOff).Resize(NumRows, NumCols).Value = Stressa

This generates a range offset from the top left cell of the range “DFileRes” by zero rows and DatOff columns, with a size of NumRows x NumCols, and writes the contents of the array “StressA” into that range.  Note that a range named “DFileRes” must be created in the spreadsheet  for the macro to work.