clear me please!

With a big amount of recorset data warth is the best in order of performance, with Acces data base?

Set RS = New ADODB.Recordset
RS.CursorType = adOpenKeyset
RS.LockType = adLockOptimistic

or

Set RS1 = New ADODB.Recordset
RS1.CursorType = adOpenKeyset
RS1.LockType = adLockReadOnly


my conn

With CONN
.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MF\DATABASE\BAN.mdb;Persist Security Info=False"
.CommandTimeout = 0
.CursorLocation = adUseClient
.Open
End With


in effect i need Readonly or Optimistic????