16.0 (for me) when on a survival world that is 70MB, the world will be pretty laggy

I'm using a MYPhone MY28S (local brand). When I'm on 15.7 my survival world was pretty smooth and playable and no lag (unless the settings is on 4 chunks. Fancy Graphics & Beautiful skies turned on). But when I updated to 0.15.90.2 the world is now pretty laggy even when I turn off fancy graphics & beautiful skies. Hope you can fix this bug