iPhone 6 lag / frame rate drop

We have a project we are putting together that has a number of moving platforms with colliders.
On these platforms there are animated characters that are basically just performing a ping-pong movement along the platforms.

We have noticed that on iPhone5 and iPad Air the project runs perfectly but on iPhone 6 when the characters come into camera view the frame rate drops terribly and becomes almost unplayable.

There are about 20 moving (translated in update) items on the screen when this happens but only four of them are skinned mesh (<1200 tris). The other "moving" gameobjects are just the platforms.

On iPhone5 and iPad Air the game runs buttery smooth but doesn't matter what I do iPhone 6 just stutters until the moving characters are out of camera view.

We have added Kinematic rigid bodies to all moving "colliders" (including the characters) changing from Generic Animation to Legacy, even removed Audio Sources from the Characters, nothing helps.

In Profiler we are seeing under 10ms in editor and no spikes in GC or any other area that makes sense.

Note: We are using Metal as our rendering API and Forward Rendering + only one direction light.

I am thinking it might have to do with fill rate (I have tried disabling nearly everything else) as I believe the iPhone 6 has a higher resolution but A7 GPU.

Is it possible to "lower" / lock the rendering resolution for the iPhone 6 to test if it is a refresh / fill rate issue?

PS. We are using Unity Pro 2017.3

Any advice or pointers would be awesome.

 

This topic can be closed, we discovered there is an issue with the iPhone 6 we were testing on as it lagged on otherwise perfect games.