The diagram notes it will also support that slower memory type too. When using LPDDR5 it supports up to 64GB of RAM. That's bumped up to 96GB when using DDR5-5600.

Intel W680 Block Diagram Leak Hints At Major Change Headed To Alder Lake Xeon CPUs by Paul Lilly — Tuesday, March 01, 2022, 12:23 PM EDT Comments ...