Performance Problem With VS2005 Code Style?

I run into a wirt asp.net sittuation, when coding my ASP.NET page using the traditional old way like this, it runs very fast:

        Dim thisSQL =" SELECT strAuthorName, strTitle, strContent, lngChapter, tblKiemHiepChapters.strReference FROM tblKiemHiepAuthors A " & _
                     " INNER JOIN tblKiemHiepTitles B ON A.ID=lngAuthorID " & _
                     " INNER JOIN tblKiemHiepChapters ON B.ID=lngTruyenID " & _
                     " AND tblKiemHiepChapters.ID="& e.CommandArgument

        Dim thisConnection As SqlConnection = new SqlConnection(ConfigurationSettings.AppSettings("DNS2"))
        Dim thisCommand As SqlCommand = New SqlCommand(thisSQL, thisConnection)
        thisConnection.Open()
        dim objReader As SqlDataReader = thisCommand.ExecuteReader()
       
        objReader.Read()
        if objReader.HasRows then
            if (objReader.Item("strTitle") Is DBNull.Value ) Then
               thisHeading = Replace(thisHeading, "#HEADING#", "" )

            else
               '''''''''''
            end if................

but when I used VISUAL STUDIO.NET way of binding datasouce like below: it runs so damn slow. do you guys know what the problem is? if you need to see the complete code please let me know. this happen when my ntext field that contains lots of text (the code post heredoes  not necessary have the same functionality)

<asp:SqlDataSource ID="GetContentByChapterID" runat="server" ConnectionString="<%$ ConnectionStrings:nangmoi_cnn_string %>"
SelectCommand="SELECT [lngChapter], [strReference], [strContent] FROM [tblKiemHiepChapters] WHERE (ID = @ChapterID)">
<SelectParameters>
<asp:SessionParameter DefaultValue=0 Name="ChapterID" SessionField="ChapterID" Type="Int32" />
</SelectParameters>           
</asp:SqlDataSource>