Testing shows that, by default, pooling is not enabled for the JET provider. Try adding 'OLE DB Services=-1' to your connection string.
See elsewhere in this thread for the performance improvement I see......

>Thanks Bill....
>
>But if pooling were active, there should not be such a drop in performance, right?
>
>In fact from what I understand, Microsoft.Jet.OLEDB.4.0 does not support pooling, which might be my problem.
>
>Have not been able to find an explicit statement somewhere that confirms that, but from my registry settings, that is what I conclude.
>
>In fact, I read somewhere that it is recommended to have one connection per client, which kind of contradicts the pooling concept.
>
>It might be that pooling only makes sense on a true dbms like sqlserver, unlike an access file that is merely shared.
>
>It's not such a big deal in itself, but it might be documented a bit more clearly, then I would not have to redesign my dataaccess classes :)
>
>
>
>
>>You're opening and closing conn inside the for loop in the second one.
>>That will hit performance.
>>Move them outside the for loop and try it.
>>
>>
>>>>
>>Check out the following tests
>>Testconnections2 returned 0.23 seconds, Testconnections3 returned 4.68 seconds, that's a factor of 20 slower. If there is any pooling done here, it's either not working for me, or it's kind of not very effective.
>>What am I missing?
>>
>> Public Sub testConnections2()
>> Dim cmd As New OleDbCommand
>> Dim da As New OleDbDataAdapter(cmd)
>> Dim conn As New OleDbConnection
>> Dim dt As New DataTable
>> conn.ConnectionString = My.Settings.b040_beConnectionString
>> conn.Open()
>> cmd.Connection = conn
>> Dim n As Long
>> Dim t As Date = Now
>> For i As Integer = 1 To 100
>> cmd.CommandText = "select Art_id from Artikel where Art_nr = ' 125'"
>> n = cmd.ExecuteScalar()
>> cmd.CommandText = "select * from artikel where Art_Nr = ' 125'"
>> da.Fill(dt)
>> Next
>> Debug.Print((Now() - t).ToString)
>> End Sub
>> Public Sub testConnections3()
>> Dim cmd As New OleDbCommand
>> Dim da As New OleDbDataAdapter(cmd)
>> Dim conn As New OleDbConnection
>> Dim dt As New DataTable
>> conn.ConnectionString = My.Settings.b040_beConnectionString
>> cmd.Connection = conn
>> Dim n As Long
>> Dim t As Date = Now
>> For i As Integer = 1 To 100
>> conn.Open()
>> cmd.CommandText = "select Art_id from Artikel where Art_nr = ' 125'"
>> n = cmd.ExecuteScalar()
>> cmd.CommandText = "select * from artikel where Art_Nr = ' 125'"
>> da.Fill(dt)
>> conn.Close()
>> Next
>> Debug.Print((Now() - t).ToString)
>> End Sub