There are already DDR5 CUDIMMs at and above 8000 MT/s, and 9600 MT/s has been demonstrated but none are currently in stock. By the time AMD ships Zen 6 desktop processors, the market should be ready with memory modules that will mean even the highest core count Zen 6 parts will be at worst only slightly more bandwidth-starved than their predecessors. And the lower core count Zen 6 CPUs with a single CCD should be able to provide substantially more bandwidth than their predecessors. All without requiring DDR6 yet.