An Extensive Look At The AMD Naples vs. Rome Power Efficiency / Performance-Per-Watt
First up was the thread-happy John The Ripper that can easily scale out to the EPYC 7742 with its 64 cores / 128 threads.
Here is a look at the AC system power consumption during the JtR run, keeping in mind it's the AC wall power and not the individual CPU socket. Additionally, no discrete graphics at play, but overall the power numbers appear to be quite good considering the TDPs of these processors.
Given that data, we see the EPYC 7002 series easily delivering much better performance-per-Watt over the previous-generation EPYC 7001 processors. The EPYC 7402 and higher SKUs were delivering better performance-per-Watt than all of the Naples parts tested, including the previous flagship EPYC 7601. Comparing the 24-core parts, the EPYC 7402 delivered 1.23x the perf-per-Watt of the EPYC 7401P, the 32-core EPYC 7502 delivered 1.2x the perf-per-Watt of the EPYC 7601, and of the flagship models there was a 1.67x improvement from the 7601 to 7742 SKUs.
Under this highly-threaded workload, the EPYC 7002 processors were successfully hitting around their maximum boost clocks and indeed clocking higher on average than the previous-generation processors.
The Noctua TR4-SP3 with the other Noctua fans inside the 4U rackmount chassis were enough to keep the processors running cool enough under John The Ripper to avoid any throttling.