[derekp7]

On the other side, a hyperthreaded CPU used to be about 10 - 30% gain, but in tests I've ran on recent hardware (HP DL380 Gen 10) hyperthreading gives around 70% more performance (the test I used was running pigz [parallel gzip] on a large file).

[greglindahl]

That's a great example of how hyperthreading's performance effects are extremely workload dependent.