Intel 9th Generation Core processors can support up to 128 GB DDR4 RAM
The upcoming Intel 9th Generation CPUs including the Core i9-9900K, the Core i7-9700K, and the Core i5-9600K can support up to 128 GB of DDR4 RAM. This was confirmed by Intel to Anandtech shortly after the 9th Generation CPUs were officially unveiled.
Traditional consumer desktops support up to 64 GB RAM i.e. two DIMMS per memory channel a.k.a. 2DPC. A typical UDIMM features 16 GB DDR4 RAM so 4x16 is the maximum limit possible currently in consumer systems. There have been some developments recently with the likes of Zadak and G.Skill introducing double height double capacity (DHDC) 32 GB DDR4 modules. Also, Samsung has started production of 16 GB RAM chips implying that 4x32 is actually possible.
This information was not really discussed by Intel or OEMs during the 9th Gen launch but HP, in one of the footnotes for their upcoming desktop platforms, said '128GB memory planned to be available in December 2018', which prompted Intel to issue a statement, which reads —
The new 9th Gen Intel Core processors memory controller is capable of supporting DDR4 16Gb die density DIMMs which will allow the processors to support a total system memory capacity of up to 128GB when populating both motherboard memory channels with 2 DIMMs per Channel (2DPC) using these DIMMs. As DDR4 16Gb die density DIMMs have only recently become available, we are now validating them, targeting an update in a few months' time."
Intel has only talked about 128 GB RAM support for the new 9th Generation CPUs and has not not talked about previous generation CPUs or support for 256 GB RAM on HEDT platforms. AMD, on the other hand, says that its memory controller already is built to support these new RAM modules but we are yet to see any validation data.
Pricing, however, is not expected to be cheap and is likely to be at least double of current 4x16 configurations. That said, upcoming mobile workstations could be employing 2x32 SO-DIMM modules soon, making DHDC modules a welcome development for professionals and content creators.