Overall, as much as 20% better on single thread using same watts x 5900x, same as 5900x on multithread using twice as much watts, so this cpu is mainly for single thread, for multithread stick with ryzen 5900x or 5950x.
This CPU is not a step in the right direction concerning watts. I miss those days where Intel would prioritize watts x performance. I wonder if you can lower the voltage on this as much as possible and see if on multithread performance drops only a little, might be worth, yeah you will lose single thread performance I guess, in the end 12900 might become a 5900 on single thread and lower multi thread performance than 5900x, maybe it can't be helped.
I will just skip this and jump straight in the next amd cpu with ddr5, things by then will have matured a lot more. If the next amd cpu can match 12900k in single thread without extrapolate watts in multithread then it's a win.