SK Hynix has recently added single-die DDR4 memory chips featuring 16 Gb capacity to its product catalog. The benefit of the increase in single-die capacity is two fold: not only will the new components enable the company to build high-capacity memory modules using fewer chips, but also it will enable SK Hynix and its partners to build 256 GB DDR4 memory modules for ultra-high-end servers.
16 Gb DRAM chips per se are not exactly a breakthrough. Memory makers, including SK Hynix, already build high-capacity DRAM components by stacking two or four 8 Gb memory dies vertically using TSVs to get 16 Gb and 32 Gb components, then use such chips to build memory modules featuring 64 GB and 128 GB density. Stacking makes organization of DIMMs very complex: in the case of a 64 GB module we are dealing with a quad-ranked DIMM (featuring two physical and two logical ranks), whereas a 128 GB module is octal ranked (featuring two physical ranks and four logical ranks). LRDIMMs have a relatively high latency in general (because they use additional buffers), meanwhile complexity of 64 GB/128 GB LRDIMM architecture forces module makers to increase them even further (to CL20/CL22 for DDR4-2400/DDR4-2666 speed bins).
https://www.anandtech.com/show/12370...o-256-gb-dimms
SK Hynix’s Product Catalog Lists 16 Gb DDR4 Chips
29th January 2018, 06:29
SK Hynix’s Product Catalog Lists 16 Gb DDR4 Chips 
