There are several different companies that design microprocessors. There is Intel, AMD, Imagination (MIPS), and Oracle (Sun SPARC) to name a few. However, none of these companies is known exclusively for their power efficiency. One company that does specialize in energy efficient processors is ARM.
Marvell launches 64-bit octa-core ARMADA Mobile PXA1936 SoC
Some people are worried about the "future proofing" of the Note 4. The worry seems to be that, if Samsung keeps the Note 4 as 32-bit only, when some models are capable of running in 64-bit mode, then the Note 4 has no future, it is doomed. Such thinking really isn't warranted. Let me explain.
64-bit Android L developer preview emulator now available
Samsung's Exynos 5433 SoC, found in some versions of the Galaxy Note 4, has been identified as a 64-bit big.LITTLE chipset with Cortex A57 and A53 processors, Mali T760 GPU on Samsung's new 20nm process. A 64-bit SoC, so why is Note 4 only 32-bit?
Why ARM’s 64-bit architecture is good for developers and good for users
The age of 64-bit mobile computing is upon us, mainly thanks to ARM. These new processors are faster and open up mobile platforms to a whole range of new possibilities, all while staying true to ARM’s low-power heritage.