At the NVIDIA GPU Technology Conference (GTC) event, Micron demonstrated huge 256GB DDR5-8800 MCR DIMMs. These modules are designed for next-generation servers, in particular, those with Intel Xeon Scalable Granite Rapids processors. Earlier, the company announced that the new 256GB MCR DIMMs are being tested among customers.
Micron showed off a large 256GB DDR5-8800 MCRDIMM, but also plans to offer standard-height MCRDIMMs. Both 256GB MCRDIMM modules are based on 32GB DDR5 crystals, but the large one places 80 DRAM chips on both sides of the module, while the standard one uses 2Hi packages, which means they heat up a bit more due to less poor heat dissipation. The module consumes about 20W, which is not bad since Micron’s 128GB DDR5-8000 RDIMM consumes 10W.
Multiplexer Combined Ranks (MCR) DIMMs have dual-rank modules that enable both ranks to operate simultaneously by using a special buffer. The buffer allows the two physical ranks to act as if they were two separate modules running in parallel. This achieves double the performance by simultaneously receiving 128 bytes of data per clock cycle. The buffer operates with its own memory controller using the DDR5 protocol, at speeds exceeding the standard, in this case 8800 MT/s.
Typically, dual physical rank modules function as a single module — when the CPU (or memory controller) receives data from such a module, it is limited to 64 bytes of data at a time. MCRDIMMs double this figure, increasing performance.
Given that Micron demonstrated its MCRDIMMs at the GTC organized by NVIDIA, it is likely that the company is positioning these products for AI servers. Such computers typically require a huge amount of memory for training, and the new high-capacity modules will come in handy. Intel Xeon Scalable Granite Rapid processors have a 12-channel memory subsystem that supports two modules per channel. Using 256GB Micron MCRDIMMs, a Granite Rapid-based server can have 3TB of DDR5 memory with 12 slots and 6TB of DRAM with 24 slots.
Source: Tom`s Hardware