Is there a way of having the 3GB of RAM?

I saw this phone has 2.5 GB of ram and i read that it is because it has the other part for the system but i have also a Nexus 6 and it runs smoother.

This phone doesn't have better multitasking and i think it is for the missing part of RAM memory.

Moto X Pure has 700MB of Android OS
Nexus 6 has 478MB...

I have tried CM13 and Stock and truepure.