Energy efficiency is a critical figure of merit for battery-powered applications. Today's embedded systems suffer from significant increase of power consumption essentially due to a high leakage current in advanced technology node. A significant portion of the total power consumption is spent into memory systems because of an increasing trend of embedded volatile memory area among the building components in System-on-Chips (SoCs). That is why new Non-Volatile Memory (NVM) technologies are considered as a potential solution to solve the energy efficiency issue. Among these NVM technologies, Magnetic RAM (MRAM) is a promising candidate to replace current memories since it combines non-volatility, high scalability, high density, low latency and low leakage. This paper explores use of MRAM into a memory hierarchy (from cache memory to register) of a processor-based system analyzing both performance and energy consumption.