Stats & FPS Monitor helps you show FPS, hardware info and various system information to the user with the Unity 5 UI so you have full control over each element and its style.
Website | Docs
* Each element is optional, what the user will see is completely up to your decision.
* Available informations:
-FPS (Minimum, Maximum, Average)
-GPU, GPU Memory
-CPU, CPU Cores, CPU Frequency
-RAM, RAM In Use
-Operating System
-Device Model
(All of them are optional and independant.)