upload extremely slow

FTPsession.PutFiles(Localpath, Remotepath, False, _transferoptions)

  Private Function Upload() As Boolean
        _Sessionoptions = New SessionOptions
        Try
            With _Sessionoptions
                .HostName = hostname
                .PortNumber = 21
                .UserName = login
                .Password = passwd
                .Protocol = Protocol.Ftp
            End With
        Catch ex As SessionException
            MsgBox(ex.Message, MsgBoxStyle.Critical)
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Critical)
        End Try

        With _transferoptions
            .TransferMode = TransferMode.Automatic
            .PreserveTimestamp = False
        End With

        'open the session and transfer file
        Dim FTPsession As Session

        Try
            FTPsession = New Session

            'continuous progress reporting
            AddHandler FTPsession.FileTransferred, AddressOf FileTransferred
            'Connect 
            Dim filepath As String = System.Reflection.Assembly.GetExecutingAssembly.Location
            ' Session.ExecutablePath =
            FTPsession.DisableVersionCheck = True
            FTPsession.Open(_Sessionoptions)
            _transferresult = FTPsession.PutFiles(Localpath, Remotepath, False, _transferoptions)
            _Sessionoptions = Nothing

            If _transferresult.IsSuccess = True Then
                Return True
            Else
                Errorlog = "Error in WinSCP "
                Return False
            End If

        Catch ex As Exception

            Errorlog = "Error in WinSCP : " & ex.Message.ToString
            MsgBox(Errorlog)
            Return False
        Finally
            FTPsession.Dispose()
            FTPsession = Nothing
        End Try

    End Function