So the new AM5 motherboard and the AMD 7xxx Zen4 chips officially debut tomorrow (2022-Sept-27) but the reviews seem to have come out today.
The big change is you need a new platform (a new board) and new RAM (DDR5). The other big change is the CPUs no longer come with an in box cooler, and they run much hotter, BY DESIGN. AMD has decided to allow the CPU to run all the way up to TJMax (95C) before throttling, which means the power utilization is going to spike significantly. The 7950X looks to run over 250W at max utilization… but it does provide about 15% better output than the Zen3 5950X. (This means output per watt actually goes down though, so if you needed a lot of output (say a video recoding or 3D render farm) you would probably be better off with two 5950X CPUs which would use about the same power as one 7950X.)
Intel has a new Raptor Lake debut coming in about a month. With the prices of DDR5 RAM being where they are, and with new GPUs in the near-term pipeline… if you’re in the market for something new, I would hold off and consider looking to see what the new year brings for price drops.