The competency of superscalar CPUs attains more dominance with the usage of simultaneous multithreading or the SMT technique. With this method, the modern processor resources can be exploited to the fullest level by the multiple independent threads. To do so these multiple threads utilizes the same clock cycle to carry out different instructions by using the execution unit that the first thread spared.
The add-ons needed to achieve this are the ability to fetch instructions from multiple threads in a cycle and a larger register file to hold data from multiple threads, where the basic processor unit remains the same. The numbers of multiple threads are usually limited to 2,4, or 8 depending on the chip complexity.