Multi threading , C#

If you did not do anything wrong (how do you know that), what's wrong?

There is no reason for System.Threading.Thread to be slower than Background worker simply because the thread behind is exact same thing. Well, maybe Backrgound/Foreground makes some difference in your case and is different in your two experiments. You can make them the same and compare -- interesting to see. We can discuss your code and try to understand where is the difference in performance. I think the issue is how clean your experiment is.

Timer: get rid of them if possible, by many reasons, always prefer thread. If you doubt if thread is applicable (doubt about incorrect timing, waste of CPU time?), maybe I can give you a better idea. Thread vs. Worker thread? OK, what's "worker thread"? This is not a special term for something certain, just a thread. Sometime people call "worker thread" a thread which is not the same as the one of application entry point, sometime -- non-UI thread, which is usually the same. There is not one vs. another. Or you mean something else? Then explain.

--SA

You're right about Component Model (one of the weakest parts in .NET in my opinion) and Forms (using component model, but the a thread itself is not related to Forms). The thread should not really depend on Forms. Even Dispatcher works the same way in Forms and WPF (basically, you always need to know Dispatcher if you use thread with UI). In brief and roughly speaking, BackroundWorkier is a thread for lamers (I no way want to say it should not be used).

Now, it's the best not to touch priority. My question is: does you thread use any kind of spin wait (a loop doing nothing really useful but checking some condition, or doing some polling)?

Most of the performance problem with threads is due to incorrect using (or not using) of wait states where the thread consumes zero CPU time until awaken by the condition (timeout, by synchronization primitive like lock or event wait handle, Abort or Interrupt). Failure to using though is a usual reason of performance leak.

--SA