The following code works if my source records from c6:e255, but when I added more records, (c6:e365), excel locks up and is not responding:
Sub Conversion()
Dim i As Long
Application.ScreenUpdating = False
Range("g5:i" & Rows.Count).ClearContents
Range("g5").Resize(, 3).Value = Array("h1", "h2", "h3")
For i = 6 To Range("c" & Rows.Count).End(xlUp).Row
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "c"), Cells(i, "d"), Cells(i, "e"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "c"), Cells(i, "e"), Cells(i, "d"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "d"), Cells(i, "c"), Cells(i, "e"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "d"), Cells(i, "e"), Cells(i, "c"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "e"), Cells(i, "c"), Cells(i, "d"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "e"), Cells(i, "d"), Cells(i, "c"))
Next
Range("g5").Resize(, 3).ClearContents
Application.ScreenUpdating = True
End Sub
Sub Conversion()
Dim i As Long
Application.ScreenUpdating = False
Range("g5:i" & Rows.Count).ClearContents
Range("g5").Resize(, 3).Value = Array("h1", "h2", "h3")
For i = 6 To Range("c" & Rows.Count).End(xlUp).Row
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "c"), Cells(i, "d"), Cells(i, "e"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "c"), Cells(i, "e"), Cells(i, "d"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "d"), Cells(i, "c"), Cells(i, "e"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "d"), Cells(i, "e"), Cells(i, "c"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "e"), Cells(i, "c"), Cells(i, "d"))
Range("g" & Rows.Count).End(xlUp).Offset(1).Resize(, 3) = Array(Cells(i, "e"), Cells(i, "d"), Cells(i, "c"))
Next
Range("g5").Resize(, 3).ClearContents
Application.ScreenUpdating = True
End Sub