I took these AIDA64 screenshots from a while ago directly comparing two of my 128GB workstations, one with a 5900x DDR4, and the new one with 7950x and DDR5.
This was before I went down from DDR5-4800 to DDR5-4600 (to avoid memory errors), so the 7950x results are very slightly higher than what I would get now.
5900x 4x32GB at DDR4-3600:
7950x 4x32GB at DDR5-4800:
When comparing to Zen3 I don’t see an issue with not being able to hit high DDR5 speeds on Zen4. Yes, I’d like it to be faster, and hope it gets better in time, but it still is faster with 4x32GB than the previous platform!
Also don’t forget the architectural differences of DDR5 (two channels per DIMM); you can’t just look at timings and understand how it’ll affect any given application since so much has changed.