Dropping Puzzle pieces without physics

I used the physics template for a puzzle game, where squares fall from the top of the all and stack at the bottom.

I wanted to know if there were tips or tricks to get this to perform well on a mobile phone.

I was thinking one way to help is when the bricks hit the bottom, they disable physics and become dormant waiting for a click instead of helping bounce things around.

Otherwise, I'm not sure.

At most I can have 30 blocks falling and doing physics calculations..