Here's an "all else being equal" example. Among the different skus from intel scalable platform we have:
Xeon 8164: 26 cores 2.0GHz (150w tdp)
Xeon 6144: 8 cores 3.5GHz (also 150w tdp)
It means dropping the clock from 3.5 to 2.0, and adding cores up to the same tdp, provides 1.86x the raw total performance and therefore 1.86x perf per watt. That 26 cores looks great on paper but the die is much bigger ($$$) and not all workloads can actually take advantage of it. Network servers are perfect for this because they run hundreds or thousands of processes with little interraction between them. I suspect the typical games on PC would be faster on the 3.5GHz for a much lower cost.
Xeon 8164: 26 cores 2.0GHz (150w tdp)
Xeon 6144: 8 cores 3.5GHz (also 150w tdp)
It means dropping the clock from 3.5 to 2.0, and adding cores up to the same tdp, provides 1.86x the raw total performance and therefore 1.86x perf per watt. That 26 cores looks great on paper but the die is much bigger ($$$) and not all workloads can actually take advantage of it. Network servers are perfect for this because they run hundreds or thousands of processes with little interraction between them. I suspect the typical games on PC would be faster on the 3.5GHz for a much lower cost.