Whether SMT a.k.a. hyperthreading is useful or not depends greatly on the application.
There is one important application for which SMT is almost always beneficial: the compilation of a big software project, where hundreds or thousands of files are compiled concurrently. Depending on the CPU, the project building time without SMT is usually at least 20% greater than with SMT, for some CPUs even up to 30% greater.
For applications that spend much time in executing carefully optimized loops, SMT is usually detrimental. For instance, on a Zen 3 CPU running multithreaded GeekBench 6 with SMT disabled improves the benchmark results by a few percent.
There is one important application for which SMT is almost always beneficial: the compilation of a big software project, where hundreds or thousands of files are compiled concurrently. Depending on the CPU, the project building time without SMT is usually at least 20% greater than with SMT, for some CPUs even up to 30% greater.
For applications that spend much time in executing carefully optimized loops, SMT is usually detrimental. For instance, on a Zen 3 CPU running multithreaded GeekBench 6 with SMT disabled improves the benchmark results by a few percent.