Selecting cells in a loop routine appears to be terribly inefficient. The code I have is:
Sub errorchk()
Dim s1, s2 As String
Dim r As Variant
Application.ScreenUpdating = False
s1 = "sheet1"
s2 = "sheet2"
For r = 1 To 100
For c = 1 To 26
Cells(r, c).Select
If Sheets(s1).Cells(r, c).Value < Sheets(s2).Cells(r, c).Value Then MsgBox "error at " & ActiveCell.Address
Next c
Next r
MsgBox "Check complete"
Application.ScreenUpdating = True
Range("a1").Select
End Sub

... but would be grateful if anyone has code that can do the same quicker as the check range needs to expand.

Thank you in anticipation.