https://www.techpowerup.c...n-5-desktop-processors
 
AMD's upcoming Ryzen 9000 series "Granite Ridge" desktop processors based on the "Zen 5" microarchitecture will see a slight improvement in memory overclocking capabilities. A chiplet-based processor, just like the Ryzen 7000 "Raphael," "Granite Ridge" combines one or two "Zen 5" CCDs, each built on the TSMC 4 nm process, with a client I/O die (cIOD) built on the 6 nm node. The cIOD of "Granite Ridge" appears to be almost identical to that of "Raphael." This is the chiplet that contains the processor's DDR5 memory controllers.

As part of the update, Ryzen 9000 "Granite Ridge" should be able to run DDR5-6400 with a 1:1 ratio between the MCLK and FCLK domains. This is a slight increase from the DDR5-6000 sweetspot speed of Ryzen 7000 "Raphael" processors. AMD is reportedly making it possible for motherboard manufacturers and prebuilt OEMs to enable a 1:2 ratio, making it possible to run high memory speeds such as DDR5-8000, although performance returns with memory speeds would begin to diminish beyond the DDR5-6400 @ 1:1 setting. Memory manufacturers should launch a new wave of DDR5 memory kits with AMD EXPO profiles for DDR5-6400.
 
So you can run higher memory beyond DDR5-6400 but stability is not guaranteed.