Well hyperthreading can help in the sense that the execution "slots" may not be wasted if the other hyperthread can use the ports that would be otherwise unused

Well hyperthreading can help in the sense that the execution "slots" may not be wasted if the other hyperthread can use the ports that would be otherwise unused if only a single thread were running. That mostly only works if the workloads of each thread have very different port usage. Consider one workload which saturates on p1, doing integer multiplication, and another one which is load/store heavy. Those two loads run on sibling hyperthreads could perhaps approach the best possible speedup of 2x since they use different ports.