There's lot of data about this, but as someone else noted it is very workload dependent. It allows you to more effectively hide memory latency, but of course y

There's lot of data about this, but as someone else noted it is very workload dependent. It allows you to more effectively hide memory latency, but of course you still have to deal with other issues like the increased register file size. A lot of modern app architectures are effectively 3 threads (UI thread, compute thread, and compositor thread), which seem like good candidates for SMT. Although I don't think many/any mobile architectures use SMT -- I don't know how it effect power efficiency.