Micron CZ120 CXL Memory Expansion Module at FMS 2023

At FMS 2023, we got to see the Micron CZ120 running live on the show floor. FMS 2022 was just before the CXL-equipped CPUs like AMD EPYC Genoa, Genoa-X, and Bergamo were launched so while we saw some devices, even hooked up to pre-production 4th Gen Intel Xeon Scalable CPUs, that never ended up supporting CXL Type-3 devices. This year, the silicon was out and CXL companies have had some time to make demos work, so it was running on the show floor.

Micron CZ120 CXL Memory Expansion Module at FMS2023

The Micron CZ120 is an E3 EDSFF device that was running in a server on the show floor.

Capacities are 128GB and 256GB, which is not huge by any means, especially when you compare the size of the drive to the size of a 256GB DIMM. Part of that is that there needs to be a CXL controller chip, power delivery, and so forth on the EDSFF module.

The way it was plugged in was quite fun. The drive was inserted into a PCIe slot that was cabled on its way back to the host system.

It was fun that Micron had this in a pre-production server rather than a production unit, especially since we are now months after the launch of servers. One major challenge is that not all servers have firmware that supports CXL and more specifically CXL Type-3 devices.

We did not hear if this was a custom controller or something from a company like Astera Labs. Still, it was great to see the demo working at the show.

Edit: We heard that Micron is the Microchip CXL controller in the CZ120.

Final Words

CXL Type-3 memory expansion devices are going to be a big deal in the near future, especially once CXL expands outside of a single chassis with devices like the XConn XC50256 CXL 2.0 Switch. That is where we can start to have memory shared among multiple servers which will in turn make infrastructure more flexible and limit stranded resources.

Now we just have to figure out how to get them.