Weird slow window update problem

I sometimes hate to post this kind of problem because I always hoped that the problem was just transient. But it has been lasting for several months or even more than one year, which I don't quite recall clearly.

 

It's like this. Many times for unknown reasons, window content is slow to update. For example, when I right click in Explorer, the menu is slow to update its content and I have to point cursor at a menu item to 'force' it to update. This problem appears to have some kind of relationship with ASUS GPU Tweaker because most the time the problem arose after I ran this tool or quit it.