when generate 10000 matrix bar code it take too much time How to make

Problem
When generating matrix 2d bar code it take per 10000 files matrix bar code generating it take 1 minute
so that how to generating matrix bar code 2d in less time as seconds .
my code as below under button generating :

Class1 CLS = new Class1();
                DataTable dt = CLS.ShowalldataSerial(textBox4.Text);

                for (int i = 0; i <= Convert.ToInt32(textBox1.Text); i++)
                {
                    Serial = SRL.Rnd().ToString();
                    txt = "UserID" + dt.Rows[0][0] + "FirmName" + dt.Rows[0][1] + "OrderNo" + dt.Rows[0][2] + "BtachNo" + dt.Rows[0][3] + "Quantity" + dt.Rows[0][4] + "ProductName" + dt.Rows[0][5] + "SerialNo" + Serial;

                    dm.DM(txt, Color.FromName(comboBox1.SelectedItem.ToString()), Color.White).Save(root + "\\" + Serial + ".emf", System.Drawing.Imaging.ImageFormat.Emf);

                }
                MessageBox.Show("Records generated success ");

when create 10000 in textbox1 it take minute if i write

200000 in textbox1 it take 20 minutes

Code working without any problem and give me result what i need

but it slowly generating data matrix per big quantities

so that what i do to make generating matrix bar code very fast .