According to Anandtech memory makers 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.

But having to stack this lot makes DIMM organisation a little complex.  LRDIMMs have relatively high latency because they use additional buffers, meanwhile complexity of 64 GB/128 GB LRDIMM architecture forces module makers to increase them to CL20/CL22 for DDR4-2400/DDR4-2666 speed bins.

SK Hynix has developed single-die 16 Gb DDR4 components which means that ICs can build client memory modules or subsystems with a fewer number of chips, lowering power consumption, and allows server-class DIMMs with densities of up to 256 GB. When it comes to servers, the 16 Gb DDR4 components will allow building dual-ranked 64 GB modules, quad-ranked 128 GB LRDIMMs and octal-ranked 256 GB LRDIMMs.

The 128 GB and 256 GB memory modules cost a bit. Crucial sells its 128 GB DDR4-LRDIMM for $3999.99 in retail so that a 2X capacity module would require much more.

SK Hynix’s 16 Gb DDR4 chips are organised as 1Gx16 and 2Gx8 and supplied in FBGA96 and FBGA78 packages, respectively. At present, 16 Gb memory components are rated to operate in DDR4-2133 CL15 and DDR4-2400 CL17 modes at 1.2 Volts. Sometime in the third quarter SK Hynix is expected to add DDR4-2666 CL19 to the lineup.