Thanks for the description. The article was confusing as to whether the CPU's stated 24x PCIe 5.0 lanes included those required for the chipset. Given that the same AM5 socket is used and X870E is similar to the X670E, this appears to not be the case, and instead the 9950X would have 28x PCIe 5.0 lanes, 4 of which are connected to the daisy-chained chipset and 24 then remain available to the motherboard vendor (nominally as 16 for graphics, 8 for NVMe). I also hadn't realised the CPU would offer 4x USB 4.0 ports directly.

Block diagram for AM5 (X670E/X670): https://www.techpowerup.com/review/amd-ryzen-9-7950x/images/...

Block diagram for AM4 (X570): https://www.reddit.com/r/Amd/comments/bus60i/amd_x570_detail...