Memory expansion has been attractive for years, and is more relevant than ever because ML models have an insatiable appetite for memory capacity. In response, XCENA has worked with Samsung to create a CXL memory expansion device that can also host SSDs and do compute. The device is called MX1, where MX stands for “Memory Xcelerator”.

On the memory expansion front, the MX1 can host up to 2 TB of DDR5 memory and connects to the host via a PCIe 6/CXL 3.2 x8 interface. The MX1 therefore has 128 GB/s of bandwidth to the host, or 64 GB/s in each direction. XCENA exposes another eight downstream PCIe 6 lanes that can be used to connect SSDs. SSD storage can be exposed as memory, with the MX1’s attached DRAM acting as a cache.

MX1’s most exciting feature is arguably a substantial amount of onboard compute. MX1’s chip hosts 3072 RISC-V cores, divided into clusters of 32 cores that share L2 caches and a data TLB. Sets of four clusters form a “subsystem”, which acts as the smallest job allocation unit. MX1 has 24 subsystems, letting it run 24 independent jobs at a time. An in-house NoC connects the subsystems to L3 cache and memory. Two Arm Cortex A53 cores handle control functions. The MX1 is fabricated using Samsung’s 4nm process and consumes 40 W.