iOS app 30 fps but laggy

Hiya, the app in unity editor and android work okay but in iOS it's very slow, the stats are showing it runs at 30 fps apparently but its very laggy and i'm getting quite a few performance errors ..

Slow frame buffer load... your app caused a frame buffer load operation by the gnu. a typical cause is failing to clear at the beginning of each frame.

also quite a few of those\

use vertex array objects (VAOs) to encapsulate vertex array configuration