Certainly not. Processing just does what you ask it to do. If your draw() method call background() at each frame and display a thousand squares at the very same place, then Processing will just run the code : clear the background and display the squares, even though it will give the same result on the screen at each frame. For such "consecutive frames re-processing" software optimizations, you have to do the job if you want it to be done.

Processing optimizes hardware display by offering double-buffering, OPENGL rendering... and every little things that make our programming practice easier ;-)