Samsung has announced that it will be producing the world's first 12 Gb LPDDR4 DRAM for mobile phones based on its 20 nm process. That's a lot of fancy talk that basically means we're probably going to start seeing huge amounts of RAM in phones and tablets soon.
The 12 Gb DRAM is the fasted DRAM chip available and offers the highest potential capacity on the market. This enables up to 6 GB of RAM to be used on a mobile device using four separate chips, which is pretty extreme for a mobile phone but now definitely possible and attainable. 6 GB of RAM will fit in what could previously only hold 3 GB of RAM, so manufacturers won't have to accommodate any extra space.
Samsung's component division has been doing increasingly well over the years thanks to its premium memory performance and Exynos chipset. There's no telling exactly when we'll start to see a whopping 6 GB of RAM in a smartphone, but if anyone is going to do it, it's probably going to be Samsung.
source: Samsung Tomorrow
More RAM is great but it makes no difference, if out-the-box the stock app & processes are using half of the RAM. Like if the phone came with 6GB RAM, 2.5-3GB would probably already be in use, before you even install anything