Samsung has just revealed their 4GB of LPDDR3 RAM for smartphones and tablets, and they even said it should become mainstream not just for tablets by the end of the year, but also for smartphones. If that's true than it's amazing news. This is not only about the huge amount of RAM that we might see in phones and tablets very soon but also about the DDR3 speed, which doubles the speed of some of the fastest RAM memories in smartphones today.
Bandwidth for high-end smartphones is about 800 Mbps for 1 GB of RAM, and with LPDDR3 it should be 1600 Mbps for the same 1 GB of RAM. The power consumption of this RAM memory should be the same or even lower than the LPDDR2 version. At 4 GB of LPDDR3, the bandwidth can reach 6.4 Gbps, which could greatly help gaming and even browsing on mobile devices.
I've been waiting for a while for devices like the Transformer to appear with 4GB of LPDDR3 RAM in them, because that's pretty much mandatory even for browsing on a PC today. For a tablet 1 GB seems pretty limit, and even 2 GB isn't all that much, although it should serve most purposes. But 4 GB means you're really future proofed with your device.
I would expect something like this to appear in Samsung's upcoming next-gen Galaxy Tab that will feature a very powerful dual core 2 Ghz Cortex A15 chip, also a powerful Mali T604 GPU, and a very high resolution of 2560×1600. All of that will need high memory bandwidth, too, and this new memory should be more than enough to handle all that, and a lot more as well.