var list = new List<CustomerDetached>();
                        while (reader.Read())
                        {
                            list.Add(
                                      new CustomerDetached
                                          {
                                              CustomerId = (int)reader["CustomerID"],
                                              TerritoryId = reader["TerritoryID"] as int?,
                                              AccountNumber = (string)reader["AccountNumber"],
                                              CustomerType = (string)reader["CustomerType"],
                                              Rowguid = (Guid)reader["rowguid"],
                                              ModifiedDate = (DateTime)reader["ModifiedDate"],
                                          });
                        }

class Program
    {
        static void Main(string[] args)
        {

            const string connection = "Data Source=SERVER\\SQL2008R2EXPRESS;Initial Catalog=testOrm;Persist Security Info='True'; User ID='sa'; Password='ewqEWQ321#@!'";

            using (var sql = new SqlConnection(connection))
            using (var linq = new DbDataContext(connection))
            {
                sql.Open();
                 // Замеры LINQ
                Execute(() =>
                {
                    var data = linq.Customers.ToList();
                });

                // Чистый фетч ридера
                Execute(() =>
                {
                    using (var reader = new SqlCommand("SELECT * FROM dbo.Customers", sql).ExecuteReader())
                    {
                        var list = new List<CustomerDetached>();
                        while (reader.Read())
                        {
                            list.Add(
                                      new CustomerDetached
                                          {
                                              CustomerId = (int)reader["CustomerID"],
                                              TerritoryId = reader["TerritoryID"] as int?,
                                              AccountNumber = (string)reader["AccountNumber"],
                                              CustomerType = (string)reader["CustomerType"],
                                              Rowguid = (Guid)reader["rowguid"],
                                              ModifiedDate = (DateTime)reader["ModifiedDate"],
                                          });
                        }
                    }
                });
            }

            Console.Read();
        }

        static void Execute(ActionDelegate action)
        {
            var sw = Stopwatch.StartNew();
            for (int i = 0; i < 10; i++)
            {
                action();
            }
            Console.WriteLine(sw.ElapsedMilliseconds);
        }
        delegate void ActionDelegate();

        private class CustomerDetached
        {
            public int CustomerId { get; set; }
            public int? TerritoryId { get; set; }
            public string AccountNumber { get; set; }
            public string CustomerType { get; set; }
            public Guid Rowguid { get; set; }
            public DateTime ModifiedDate { get; set; }
        }
    }