Parallel SqlDataReader and reader.Read() Slow

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SQL

threads

multi-threading

C#5.0

, +

I want to do a consult in Parallel mode, or which is the better way to do the consult to SQL.

The consult spends 3 minutes doing 7 cycles from 7 stocks, but I need that spend less time, maybe by doing the 7 consults at the same time and return the result.

My problem with the code is that reader.Read() maybie shock between the consults.

List<List<clsExistenciaA>> ListaExistencia = new List<List<clsExistenciaA>>();
SqlConnection objConexion = new SqlConnection();//conexion a sql
try
{
    objConexion.ConnectionString = @"Database=DataDB;Data Source=local;User Id=sa;Password=20011$;MultipleActiveResultSets=True";
    objConexion.Open();
}
catch { MessageBox.Show("No se puede conectar al servidor"); }

try
{
    string almacen;
    int i = 0;
    foreach(clsExistenciaA A in AlmaceneS)
    {
         //Parallel.ForEach(AlmaceneS, clsExistenciaA =>
         //{
         //    lock (AlmaceneS)
         //    {
         //        almacen = clsExistenciaA.CodigoAlm;
         almacen = A.CodigoAlm;

         SqlCommand comm = new SqlCommand();//crea command
         comm.Connection = objConexion;// se agrega la conexion al comando
         comm.CommandType = CommandType.Text;// se define el tipo de comando
         string sql = "";

         sql = "select c_codigo_alm, v_nombre_alm from invalmacen (nolock) where c_pedido_alm='almacen'";
         comm.CommandTimeout = 1000;
         comm.CommandText = sql;// se agrega la consulta a el comando
         SqlDataReader reader = comm.ExecuteReader();// se ejecuta el comando en un data reader

         ListaExistencia.Add(new List<clsExistenciaA>());
         string piezaN = "0";
         string kiloN = "0";

         while(reader.Read())
         {
             if (reader["pieza"].ToString() != "")
             {
                piezaN = reader["pieza"].ToString();
             }
             if (reader["kilos"].ToString() != "")
             {
                 kiloN = reader["kilos"].ToString();
             }

             ListaExistencia[i].Add(new clsExistenciaA()
             {
                 pro = reader["pro"].ToString(),
                 nompro = reader["v_nombre_pro"].ToString(),
                 pieza = Math.Round(double.Parse(piezaN), 2),
                 kilos = Math.Round(double.Parse(kiloN), 2),
                 CodigoAlm = almacen,
              }); // se agregan los datos a un Ilist

          }

          reader.Close();

     }
     ////}
     //});
    return ListaExistencia;
}