CardView has extra margin in each edge on Pre-Lollipop

Question

Here are two pictures.

on Lollipop:

on Pre-Lollipop:

Answer 1

I realise this has already been answered, but I'd like to add that in addition to card_view:cardPreventCornerOverlap="false", I also had to set CardView.setMaxCardElevation(0) to get rid of the margins on pre-Lollipop. Setting the elevation only to 0 did not work. I'm using support library v23.4.0.