>>105986518
They're getting the next set of CPU releases, these might be APUs (new -G SKUs).
https://overclock3d.net/news/cpu_mainboard/msi-enables-future-cpu-support-with-amd-am5-motherboard-bios-updates/

Will they get Zen 6 support? Probably.
B840 boards are missing PCIe 5 lanes and have fewer USB ports.
They appear to have fewer VRMs, but board manufacturers will just set restrictive power limits.
I see a 9950X3D being compatible with an MSI B840 board.