[roeles]

I don't think you can make general statements about STL. I have seen a Pi4 outperform a core i7 in very specific cases. That was really unexpected.

In other cases I saw a lot of runtime spent on std::map.

I think the best advice is: learn to use a profiler.

[tsegratis]

From memory, std::map is comparatively slow because the spec requires pointers to indices to be stable. In practice it is slow; see khash and many others

Personally i don't think this matters too much; you're using c/c++; you're already fast