I didn't look at source code, but I feel that units visible by friendly unit but not in camera view is still rendered. This is annotable on slow computers when it's crowd on screen or after Sattelite Uplink build - game is slowing down even I don't look at that carnage. It shouldn't be that. Units that not in view should be hidden, it can boost FPS a bit. Also not visible terrain tiles shouldn't be rendered. All modern games using this method to gain fpses.
Tell what you think.