Page "Simultaneous multithreading" Paragraph 3

Because the technique is really an efficiency solution and there is inevitable increased conflict on shared resources, measuring or agreeing on the effectiveness of the solution can be difficult.

However, measured energy efficiency of SMT with parallel native and managed workloads on historical 130nm to 32nm Intel SMT ( Hyper-Threading ) implementations found that in 45nm and 32nm implementations, SMT is extremely energy efficient, even with inorder Atom processors.

In modern systems, SMT effectively exploits concurrency with very little additional dynamic power.