It is pretty straight forward. In the new CG you can see some added electrical components inside the red circle of the picture. On the old Matrix board those components are not there.

[caption id="attachment_201" align="aligncenter" width="500" caption="Xbox 360 CG Controller Common Ground"]Xbox 360 CG Controller Common Ground[/caption] [caption id="attachment_202" align="aligncenter" width="500" caption="Xbox 360 Matrix Controller"]Xbox 360 Matrix Controller[/caption]