iOS Antialiasing performance impact too large compared to Android

I am testing AA on iOS. I am making a Google Cardboard VR app so AA is pretty important if it can be used.
On Android, turning on AA has very little impact. I tested on samsung s7 edge and it's just a few fps (3 or 4 frames) drops from original 30 fps. (The cardboard cannot use multithreaded rendering, so it's slow under a 100k triangle scene, rendered once for each eye)
However, on iPhone 6S Plus, AA downs my app from 58 fps (same 100k triangle scene with 2 eyes) to 30 fps, at any level of AA (2X, 4X or 8X).

For a simple scene with 300 triangle:
Android: 60 (no aa) -> 60 (aa)
iOS: 60 (no aa) -> 35(aa)

Is there a way to reduce the performance impact of AA on iOS?

 

hey, sry for necroing the old thread. But how did you even manage to get AA working on ios. It is completely ignored for me (2017.2.0p4) and latest gvr sdk(GoogleVRForUnity_1.110.0). It is working fine on android.