Originally HT was supposed to be transparent. According to whom? I don't think anyone with a clue would have suggested that. If you care about writing high-per

Originally HT was supposed to be transparent. According to whom? I don't think anyone with a clue would have suggested that. If you care about writing high-performance code, you care about the behavior of your processor. Obviously, multiplexing the execution of two program threads onto a single physical core is going to affect performance, whether in the form of scheduling differences, caching effects, etc. they should have dropped HT and go for actual cores instead. Well, you can do both, of course. If HT gets you better utilization of a single core, then fair enough. The question is really whether the transistors/power you burn on HT would be better spent on additional cores (or bigger caches, etc.).