Shader memory consumption.

Hi. I've met a huge memory consumption of standard shaders on iOS platform.The profiler shows that the top 3 shaders cost about 70MB memory while it just costs 1.7MB each on Mac player.

Here is my GraphicsSetting while I will load the assets from assetbundles which do not have shader exported.

I wonder why it costs so much memory and how can I reduce the memory consumption?

iOS 9.2

Unity mac 5.2.2f1