- Apr 21, 2017
How exactly do you know this? Does throughput increase less than power with SMT?
Perf/Watt should decrease without SMT.
However, sparse thread and single thread performance should see advantages, as boost can be sustained longer and higher frequencies can be hit.
With 7nm being so temperature sensitive, and power density and local heat also an issue, a few idle execution units on the average are a very good thing if all you care about is high frequencies.
Maybe most importantly , there is never unintentional loss of performance to thread from the OS tasksetting it to an occupied core (In real life, misconfigurations and suboptimal execution is probably the norm rather than the exception), as well as a higher consistency of what a thread gets in terms of resources, including caches such as the L1 and L2. .