Exploring The Zen 5 SMT Performance With The AMD EPYC 9755 "Turin" CPU
While SMT isn't beneficial everywhere, there still are many workloads where Simultaneous Multi-Threading is a valuable asset even with today's very high core count processors. Even with a 128-Core Zen 5 "classic" processor, there are a lot of workloads showing sizable gains for SMT with the EPYC 9755 and 12 channel DDR5-6000 memory. For those typically just running many heavy HPC workloads and the like, SMT can always be disabled from the BIOS or at boot/run-time within Linux for those not interested in it if your common workloads are negatively impacted.
For workloads able to benefit from SMT, it's still a clear win with AMD EPYC 9005 processors. When looking at all of the CPU power consumption across 170+ benchmarks taking ~13 hours to complete, the data here shows no power consumption difference overall to having SMT enabled. The AMD EPYC 9755 was consuming 324~326 Watts on average with a peak of 500 Watts during this wide mix of workloads tested. Those wanting to dig into even more AMD EPYC Zen 5 SMT numbers can see this result file for all of the data. SMT is also found with the "Turin Dense" Zen 5C cores and I'll have some similar SMT numbers for reference there with the 192-core / 384-thread EPYC 9965 in the coming weeks.
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