Problem with FPS and performance when switching mobile.

Hello community, this is my problem.
Seven months ago I began to develop a 3D game in unity for android.
In all moment I tried to get 60 fps, and the game worked perfectly.
I tested the game in my Samsung Note 3 Neo and hoy I said it works with 60 fps.
But one week ago I have changed my mobile phone to a Huawei Ascend Mate 7.
The new mobile is best than the other, the processor is better, and all games works better in the huawei tahn in the Note 3 Neo.
But not my game. Now my game is getting about 20 fps in huawei. I don't understand why.
Furthemore shadows looks very bad. I change all Quality setting, I have made a lot of proofs but nothing. I don't know how solucionate it.
If someone knows whats happening, I would appreciate it.
Thank you for the attention and sorry for my English.