Memory: CUDIMM on AMD

If you’re using an AMD platform-based system with the newly Clocked Unbuffered memory modules (CUDIMM) then you may see the following screen before your system boots in the operating system. 

This message usually only appears once. If you accept it, most likely, won’t appear again until you refresh your motherboard’s BIOS.

CUDIMM modules can run in bypass mode or in single/dual PLL mode.
Currently, on AMD platforms only the bypass mode is supported.

In fact, bypass mode makes the modules to behave like traditional UDIMM modules without buffering any signals or clocks.

You can read more about CUDIMM in Corsair Explorer.
https://www.corsair.com/us/en/explorer/diy-builder/memory/understanding-corsair-cudimms-a-technical-deep-dive/