MrSeb writes "Invensas, a subsidiary of chip microelectronics company Tessera, has discovered a way of stacking multiple DRAM chips on top of each other. This process, called multi-die face-down packaging, or xFD for short, massively increases memory density, reduces power consumption, and should pave the way for faster and more efficient memory chips. Multi-die face-down packaging is exactly what it sounds like, with memory dies stacked on top of each other like roofing tiles. Much like a normal desktop DIMMs and laptop SO-DIMMs, each of the stacked dies is wired to each other in series — but in this case, the connections are much shorter, as they only have to run a few micrometers to the chip below it. This is where all of the power and speed enhancements come from: shorter interconnects mean less power is needed (and thus less heat is dissipated) and signals propagate faster."
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