How to improve the speed of VBA macro code?

Question

I do not have much experience with writing macros, and therefore need the help of this community for the following issue encountered:

My macro copies a range of valu

Answer 1

.Cells(nextRow, 3).PasteSpecial Paste:=xlPasteValues, Transpose:=True Application.CutCopyMode = False

I wouldn't do that. Cut,copy & Paste operations are the costliest operations, in terms of processor utilization, in an operating system.

Instead, you could just assign the value from one cell / range to an another cell / range, as in

    Cells(1,1) = Cells(1,2)  or Range("A1") = Range("B1")

Hope you got my point..

Answer 2

As suggested by a few others in the comments, you should definitely change Application.Calculation to xlCalculationManual and rememeber to set it back to xlcalculationAutomatic at the end. Also try setting Application.Screenupdating = False (and turning that back on again too). Also, bear in mind that .Copy is a very inefficient way to copy cell values - if you really just want the values, loop through the range setting .Value to the .Values in the old range. If you need all the formatting, you're probably stuck with .Copy.

When you turn off the calc/screen refresh flags, please remember to turn them back on in all circumstances (even when your program exits at a different point, or causes a runtime error). Otherwise all sorts of bad things will happen. :)

Answer 3

Just reiterating what has already been said:

Option Explicit

Sub Macro1()

'turn off as much background processes as possible
With Excel.Application
        .ScreenUpdating = False
        .Calculation = Excel.xlCalculationManual
        .EnableEvents = False
End With

    Dim historyWks As Excel.Worksheet
    Dim inputWks As Excel.Worksheet

    Dim nextRow As Long
    Dim oCol As Long

    Dim myCopy As Excel.Range
    Dim myTest As Excel.Range

    Dim lRsp As Long

    Set inputWks = wksPartsDataEntry
    Set historyWks = Sheet11

      'cells to copy from Input sheet - some contain formulas
      Set myCopy = inputWks.Range("OrderEntry2")

      With historyWks
          nextRow = .Cells(.Rows.Count, 1).End(Excel.xlUp).Offset(1, 0).Row
      End With

      With inputWks
          Set myTest = myCopy.Offset(0, 2)

          If Excel.Application.Count(myTest) > 0 Then
              MsgBox "Please fill in all the cells!"
              GoTo QuickExit
          End If
      End With

      With historyWks
          With .Cells(nextRow, 1)
              .Value = Now
              .NumberFormat = "mm/dd/yyyy hh:mm:ss"
          End With
          .Cells(nextRow, 2).Value = Excel.Application.UserName
          oCol = 3
          myCopy.Copy
          .Cells(nextRow, 3).PasteSpecial Paste:=Excel.xlPasteValues, Transpose:=True
          Excel.Application.CutCopyMode = False
      End With

      'clear input cells that contain constants
      With inputWks
        On Error Resume Next
           With myCopy.Cells.SpecialCells(Excel.xlCellTypeConstants)
                .ClearContents
                Excel.Application.Goto .Cells(1) ', Scroll:=True
           End With
        On Error GoTo 0
      End With

    Calculate

QuickExit

With Excel.Application
        .ScreenUpdating = True
        .Calculation = Excel.xlAutomatic
        .EnableEvents = True
End With

End Sub

I'd step through the macro line-by-line to try to locate which line is slow.

Another alternative - although not sure if it'll speed things up - is to avoid the clipboard and lose the copy/paste so you'd apply a method like the following to move the data:

Option Explicit

Sub WithoutPastespecial()

'WORKING EXAMPLE

Dim firstRange As Range
Dim secondRange As Range

Set firstRange = ThisWorkbook.Worksheets("Cut Sheet").Range("S4:S2000")
With ThisWorkbook.Worksheets("Cutsheets")
    Set secondRange = .Range("A" & .Rows.Count).End(Excel.xlUp).Offset(1)
End With

With firstRange
      Set secondRange = secondRange.Resize(.Rows.Count, .Columns.Count)
End With
secondRange.Value = firstRange.Value

End Sub

Answer 4

Please take a look at this article as well. How to speed up calculation and improve performance...

By all means, Application.calculation= xlCalculationManual is usually the culprit. But we can notice that volatile Excel sheet functions can mostly kill your application on large scale of data processing and functional aspect.

Also, for your current code following post might not be directly relevant. I find it useful for tips on over-all Excel/VBA performance optimization.

75 Excel speeding up tips

PS: I don't have enough reputation to comment on your post. So added as an answer..

Answer 5

Just a few suggestions (would have posted as a comment but I guess I don't have the rep):

1. Try refering to cell addresses instead of named ranges (doubt this would be the cause but may be causing some hit to performance)

2. Do your workbook formulas contain links to other workbooks? Try testing the code on a file with broken links to see if it improves performance.

3. If neither of these are the issue, my guess is that if the formulas are overly complex, there is probably some processing overhead being added. Try the code on a file containing only values to see if there is any improved performance.

Answer 6

Best way to improve performance based on my experience is to work on variables in code rather than accessing the spreadsheet every time you want to lookup a value. Save any range you want to work with in a variable(variant) and then iterate through it as if it was the sheet.

    dim maxRows as double
    dim maxCols as integer.
    dim data as variant
with someSheet
    maxRows = .Cells(rows.count, 1).end(xlUp).row             'Max rows in sheet
    maxCols = .Cells(1, columns.count).end(xlToLeft).column   'max columns in sheet
    data = .Range(.Cells(1,1), .Cells(maxRows, maxCols))      'copy range in a variable
end with

From here you can access the data variable as if it was the spreadsheet like - data(row, column) with MUCH MUCH faster read speed.