Unlike a lot of Android OEMs, Samsung makes many of the components that go into devices in-house. Its chip powers not just Samsung devices, but a large chunk of all phones. Samsung's newest memory chips rely on new manufacturing tech that packs in a full gigabyte of RAM on a single die. That would make it economical to get a whopping 4GB of RAM in a phone or tablet.

Industry’s-First-8Gb-LPDDR4-Mobile-DRAM-02메인

The new chip is the first 8Gb low power double data rate 4 (LPDDR4) module – the low-power variant of RAM is used in phones and tablets where battery power is at a premium. Four of these chips together (remember 8 bits to the byte) makes for a 4GB package. Samsung's last generation LPDDR3 DRAM modules were only 4 and 6Gb in size. These new chips are based on a 20nm process technology with the components packed close together for higher memory capacity. Samsung claims that makes it the highest density RAM in production at this time, and that the data rates will be twice that of the LPDDR3 DRAM powering most current devices while using 40% less energy. 

All Android devices in production right now are running on 32-bit ARM processing cores, which limits the amount of addressable memory space to 4GB. To take advantage of more than 4GB of total memory, a phone needs a 64-bit chip. After Apple announced the iPhone 5S with a 64-bit processor, several manufacturers tripped over each other to say they planned to release 64-bit phones in the future. Samsung was among them, and building 4GB of RAM into a device would bring the company right up to the wall – the first Exynos chips with ARMv8 64-bit support might be just around the corner. The 8Gb chips are going to be available soon.

[Samsung]