How to increase background task performance in WPF?

I am creating a WPF application that will do the hard work in the background. The problem is that when I run the task in unit tests, it usually takes about 6-7 seconds to run. But when I launch it using TPL in a WPF application, it takes 12 to 30 seconds to start. Is there a way to speed this thing up. I am calling the COM api LogParser to do the real work.

Update : My code to call Log Parser API looks below

var thread = new Thread(() =>
            {
                var logQuery = new LogQueryClassClass();
                var inputFormat = new COMEventLogInputContextClassClass
                {
                    direction = "FW",
                    fullText = true,
                    resolveSIDs = false,
                    formatMessage = true,
                    formatMsg = true,
                    msgErrorMode = "MSG",
                    fullEventCode = false,
                    stringsSep = "|",
                    iCheckpoint = string.Empty,
                    binaryFormat = "HEX"
                };
                try
                {
                    Debug.AutoFlush = true;
                    var watch = Stopwatch.StartNew();
                    var recordset = logQuery.Execute(query, inputFormat);
                    watch.Stop();

                    watch = Stopwatch.StartNew();
                    while (!recordset.atEnd())
                    {
                        var record = recordset.getRecord();
                        recordProcessor(record);
                        recordset.moveNext();
                    }
                    recordset.close();
                    watch.Stop();
                }
                catch
                {
                }
                finally
                {
                    if (logQuery != null)
                    {
                        Marshal.ReleaseComObject(logQuery);
                        GC.SuppressFinalize(logQuery);
                        logQuery = null;
                    }
                }
            });
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
        thread.Join();

Now with this change, I see an improvement of 3-34 in debug mode, but not when I press Ctrl + F5 to start it, which is completely outside of me. How did it happen?