Four terabytes, on one specific condition
In the photo published by ASRock Rack, the display placard identifies the board as the DMRD16-2L+. The two blue rows on either side of the socket each have eight slots. Each slot serves one memory channel on Intel’s upcoming Diamond Rapids Xeon. The processor can therefore access sixteen separate channels with just one module per channel. Adding capacity and increasing the number of paths between CPU and memory are two distinct benefits here.
Reaching the 4 TB limit requires 256 GB 2U MRDIMMs in all sixteen slots. Even a full set of 128 GB RDIMMs tops out at 2 TB. The maximum advertised transfer rate also depends on the module family. The table lists the figures shown at the stand. The speed an assembled server will reach may differ.
Module type | Capacity per module | Capacity across 16 channels | Maximum advertised transfer rate |
|---|---|---|---|
DDR5 RDIMM | 128 GB | 2 TB | 8,000 MT/s |
DDR5 MRDIMM | 128 GB | 2 TB | 12,800 MT/s |
DDR5 MRDIMM, 2U form factor | 256 GB | 4 TB | 12,800 MT/s |
Where do you plug in an expansion card?
In a desktop PC you would normally insert the GPU into a long PCIe slot. Here, the connections run through up to sixteen MCIO connectors wired for ×8 each. Together they provide up to 128 lanes supporting PCIe 6.0 or CXL 3.0. A system integrator can route them to expansion slots elsewhere in the chassis or to its storage bays. A desktop graphics card therefore cannot plug directly into these connectors. The close-up taken by ServeTheHome at the stand shows four of these connectors between the socket and the memory slots.
There is still room for a local SSD on the board. The M.2 slot supports 2260, 2280 and 22110 drives over a PCIe 5.0 ×4 link. ASRock Rack also separates remote management from ordinary network traffic, with an ASPEED AST2700 management controller, a dedicated IPMI port and two 1 Gbit/s Ethernet ports.
A 33 cm board won’t fit just any tower
The EEB board measures 12 × 13 inches, or roughly 30.5 × 33 cm. A case that supports wide boards may have enough room for the PCB. The mounting points, the height of the 2U modules and the routing of the MCIO cables still need checking. Case width alone does not guarantee compatibility.
This layout comes into its own in machines that need to keep large volumes of data close to the processor. The memory installed around the Xeon is also distinct from an accelerator’s own memory, a difference illustrated in our overview of the ASUS GB300 workstation.
Key takeaways
The DMRD16-2L+ shows what a server designed around its sixteen memory channels can look like. The specifications are those of the board on display. The documents we consulted give neither a price nor a release date.