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Hyperthreading doesn't even get close to doubling actual performance, it depends on the workload but AMDs Zen5 gains about 15% from HT on average according to P
by jsheard 2y ago
Hyperthreading doesn't even get close to doubling actual performance, it depends on the workload but AMDs Zen5 gains about 15% from HT on average according to Phoronix's benchmarks.
https://www.phoronix.com/review/amd-ryzen-zen5-smt/8 https://www.phoronix.com/review/amd-ryzen-zen5-smt/8
- phkahler 2y agoIn practice on Zen1 and Zen3 I found HT to provide 20% to 25%. It seems some benchmarks are as high as 50% with zen5. AMD really improved HT with Zen 5 by adding a second instruction decoder per core. I expect even better per-thread performance from Zen 6.
- Twirrim 2y agoThere's also the added fun that using hyperthreading/SMT cores impacts your workload on the corresponding primary cores as well. Depending on your workload SMT can end up being a throughput/latency trade off you might not have been aware of. Ampere doesn't do SMT, so you get comparable performance across the board.