Over at last week's CES 2020 in Las Vegas, AnandTech got to see some DDR5-4800 RDIMM at the SK Hynix booth. DDR5 is believed to be ready for the server market in 2021. The first known platform to support DDR5 will be Intel's Xeon "Sapphire Rapids", which will be used for the Aurora supercomputer. AMD's plans for DDR5 are still unknown but perhaps they will beat Intel to the punch. At the moment, it's not known when there will be a consumer version of DDR5.
At the trade show, SK Hynix demonstrated its 64 GB DDR5 RDIMM with ECC rated for a 4800 MT/sec/pin data transfer rate. The module marked as HMCA8GR8MJR4C-EB carries 20 memory chips marked as H5CNAG4NMJ as well as IDT’s P8900-Z2 register clock driver (RCD). The memory devices are marked differently than the ones SK Hynix used for 16 GB RDIMM back in late 2018, though we do not know the difference.