When I select text in my 'favorite' browser Firefox and I drag it, I can hear un unpleasant sound from within my laptop (I think it's the videocard). That's not a real problem to me.

What does bother me is that when I select some text and drag it my KWin reacts incredibly slow, and sometimes it ends with a message that KWin has been disabled. From that moment, dragging goes fast as it should be, without any noise.

What's this? Do others have also a slow drag and drop?
Is there a way to disable KWin Drag and Drop effects? I can't find it, but I'm sure it's somewhere...