WebForms ReportViewer and poor performance when creating CSV report

Hi.

I have WebForms ReportViewer (Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) which has ProcessingMode as Remote and it's using Stored Procedure to fetch data from database.

Code for Report in Backend is below:

string userId = <Getting UserId>
string companyId = <Getting Company Id>

this.ReportViewer1.Style.Add("display", "table");
this.ReportViewer1.ServerReport.ReportServerUrl = new Uri(Configuration.ReportingServerUrl);
this.ReportViewer1.ProcessingMode = Microsoft.Reporting.WebForms.ProcessingMode.Remote;

this.ReportViewer1.ServerReport.ReportServerCredentials = new ReportServerCredentials(_userName, _userPassword, _userDomain);

this.ReportViewer1.ServerReport.ReportPath = reportPath;
List<ReportParameter> parameters = new List<ReportParameter>();
parameters.Add(new ReportParameter("UserID", userId));
parameters.Add(new ReportParameter("CompanyID", companyId));

if (_reportName == PageBase.ReportNames.CSVExport)
{
parameters.Add(new ReportParameter("Language", System.Globalization.CultureInfo.CurrentCulture.TextInfo.CultureName));
}

this.ReportViewer1.ServerReport.SetParameters(parameters);
this.ReportViewer1.ServerReport.Refresh();

Problem is that when User launch Report in ASP.NET Werforms Userinterface it's very slow. But if I run Report's Stored Procudure in SQL Server Management Studio Stored Procedure is much more faster and results comes quite quickly into SQL Server Management's Result Window.

So what is usually wrong in this kind of situation? Is WebForms ReportViewer component in WebForms Application a bottleneck when there are quite much data to be shown and if so are there any ways to configure it? Report is done by other Developer quite meany years ago.

Are there any other ways to improve performance of this kind of performance issue and/or find reason for quite poor performance?

Best Regards

Michael