If your typical workloads are covered by Phoronix tests, take a look at their energy consumption results. In LLVM compilation, for instance, 9950X does run at higher average power (188W vs 140W for 5950X), but because it finishes the task much faster, its energy consumption is actually lower at 58500 joules per run vs 78700 joules per run for 5950X, so it should be more efficient.