Speeding Up VBA execution

waygar 

Try this version:

Sub Switch()
    Dim v As Variant
    Dim NRows3 As Long
    Dim I As Long
    Dim tmp1, tmp2, tmp4

    Application.ScreenUpdating = False
    Application.Calculation = xlCalculationManual

    NRows3 = 25330
    v = Range("E6:I" & NRows3).Value
    For I = 1 To UBound(v)
        tmp1 = v(I, 1)
        v(I, 1) = v(I, 3)
        v(I, 3) = tmp1
        tmp2 = v(I, 2)
        tmp4 = v(I, 4)
        v(I, 4) = v(I, 5)
        v(I, 2) = tmp4
        v(I, 5) = tmp2
    Next I
    Range("E6:I" & NRows3).Value = v

    Application.Calculation = xlCalculationAutomatic
    Application.ScreenUpdating = True
End Sub

Please test on a copy of the worksheet.