It's been 40 years in the making. This week Samsung finally announced they've kicked phase-change memory (PCM) into mass production. In a nutshell, PCM stores information by melting and freezing microscopic crystals. In gadgets like cell phones, its frozen-in-place nature means lightning-fast bootup times--instantaneous, even.

Part of PCM's current appeal is that it actually works better the smaller it gets, unlike flash memory, which is the current go-to for small devices. Since flash memory saves data as small groups of electrons, the smaller the area you have to work with, the fewer electrons will fit, thus making the memory increasingly unstable.

PCM, on the other hand, actually benefits from shrinking, for a simple reason: smaller crystals melt and freeze faster. Matthias Wuttig, a physicist at RWTH Aachen University in Germany, has developed PCM cells that can switch on in 19 nanoseconds