Application.doevents

in which scenario are you using DoEvents? That will never speed up an application, it will only give some time to other thread like the UI thread to update

Thanks! Its mainly about when the screen is refeeshing

there isn't much you can do (other then calling DoEvents) or you need to introduce tasking

Similar to other comments, I would recommend putting the intensive processing into another thread so you shouldn't need to call Application.DoEvents() at all. You could use a background worker, ThreadPool.QueueUserWorkItem, task parallel library (aka async/await). I think async/await is probably the most familiar pattern for other programmers lately.

Is system.windows.forms.application.doevents better ? than just Application.doevents?

The same.

Thanks Andy!