Crystal Report Viewer very slow

private void button1p_Click(object sender, RoutedEventArgs e)
        {
            Windows.CrystalReportViewerWindow wnd = new ePAM.Windows.CrystalReportViewerWindow();
 
            // Change 'OperationalUnitTableAdapter' to appropriate adapter.
            ePAM.Reports.StrategyDataSetTableAdapters.OperationalUnitTableAdapter adapter = new ePAM.Reports.StrategyDataSetTableAdapters.OperationalUnitTableAdapter();
            adapter.Connection.ConnectionString = BusinessLayer.BusinessLayer.GetConnectionString();
            adapter.Fill(dataSet.OperationalUnit);
 
            // Change 'Operational_Units' to appropriate report.
            Reports.Print.Operational_Units objReport = new Reports.Print.Operational_Units();
 
            // Change 'dataSet.OperationalUnit' to 'dataSet.***'.
            objReport.SetDataSource(dataSet);
 
            wnd.MyReportViewer.ReportSource = objReport;
            wnd.MyReportViewer.RefreshReport();
            wnd.ShowDialog();
 
        }