Obout Grid Very Slow while binding huge data in my Web application using c#

Am Using OboutGrid to Display the data in my Webforms..this is cool when am binding small data..but when am binding huge data it takes more time to display the records rather than normal datagrid.any one suggest me how can i improve the performance..

 thanks in Advance

  <obout:Grid ID="GridView1" runat="server" AllowAddingRecords="false" 
          AutoGenerateColumns="false" CallbackMode="true" 
  FolderStyle="styles/style_13" Serialize="true" ShowColumnsFooter="true"  ShowGroupFooter="true"
          onrowdatabound="GridView1_RowDataBound" PageSize="-1" 
                    PageSizeOptions="1,2,3,4,5,6,7,8,9,10,50,100,500,-1">
  <Columns><obout:Column DataField="OrgName" HeaderText="OrgName" ReadOnly="true" Width="200" />
 <obout:Column DataField="Date" HeaderText="Date" Width="100" />
 <obout:Column DataField="TotalBills" HeaderText="TotalBills" Width="92" HeaderAlign = "Right" Align="Right"/>
 <obout:Column DataField="Qty" HeaderText="Qty" Width="120" Align="Right" HeaderAlign = "Right"/>
 <obout:Column DataField="GrossSale" HeaderText="GrossSale" Width="150" Align="Right" HeaderAlign = "Right"/>
 <obout:Column DataField="VAT" HeaderText="VAT" Width="120" Align="Right" HeaderAlign = "Right"/>
  <obout:Column DataField="NetSales" HeaderText="NetSale" Width="150" Align="Right" HeaderAlign = "Right"/>
 </Columns>
  <ScrollingSettings ScrollWidth="950" ScrollHeight ="245" />
  <ExportingSettings ExportColumnsFooter="true" ExportGroupFooter="true" ExportGroupHeader="true" />
  </obout:Grid>



    protected void GridView1_RowDataBound(object sender, Obout.Grid.GridRowEventArgs e)
    {
        if (e.Row.RowType == Obout.Grid.GridRowType.DataRow && status == false)//Obout.Grid.GridRowType.DataRow
        {

            mtotalBills += int.Parse(e.Row.Cells[2].Text);
            mQty += decimal.Parse(e.Row.Cells[3].Text);
            mGrossSale += decimal.Parse(e.Row.Cells[4].Text);
            mVat += decimal.Parse(e.Row.Cells[5].Text);
            mNetSale += decimal.Parse(e.Row.Cells[6].Text);

        }
        else if (e.Row.RowType == Obout.Grid.GridRowType.ColumnFooter)//Obout.Grid.GridRowType.ColumnFooter
        {
            e.Row.Cells[1].Text = "Totals : ";
            e.Row.Cells[2].Text = mtotalBills.ToString();
            e.Row.Cells[3].Text = mQty.ToString();
            e.Row.Cells[4].Text = mGrossSale.ToString();
            e.Row.Cells[5].Text = mVat.ToString();
            e.Row.Cells[6].Text = mNetSale.ToString();
            status = true;
        }
    }