> And my hash map was faster than the one in the C++ STL last I checked. Last time I checked, benchmarking hash-maps, or FWIW any other data structure, in the

> And my hash map was faster than the one in the C++ STL last I checked. Last time I checked, benchmarking hash-maps, or FWIW any other data structure, in the vacuum did not make much sense to me. Microbenchmarks cannot mimic or predict end user workloads well enough, at least in the cases where it's worth it. That said, each implementation has its own trade-offs and in particular the one from C++ STL opted in for the pointer stability. For that reason alone, which I think is quite worthy, open-addressing conflict resolution is out of the question because it cannot give such guarantees. With that in mind, if you're ok that a pointer to your key-value pair can all of the sudden be _invalidated_ by the mere operation of inserting or erasing yet another element from your hash-map, then of course, you can trade robustness for a more cache-friendly conflict resolution algorithm. But then again, this says nothing about the potential performance improvement unless you're able to measure it.