It's a little known fact that IBM creates its SMT-8 cores by taking two of its SMT-4 cores, having one stand on the other's shoulders, and draping a trenchcoat

It's a little known fact that IBM creates its SMT-8 cores by taking two of its SMT-4 cores, having one stand on the other's shoulders, and draping a trenchcoat over them so they count as one core for Oracle licensing. The trenchcoat being a de minimis ability to reschedule work from one half to the other. Seriously the per-thread performance you get from 1 thread on an SMT-4 core, 1 thread on a SMT-8 core, and 2 threads on an SMT-8 core are all extremely close together.