I've never benchmarked against postgres, but would be interested about the results. I once tried monetdb, and it was orders of magnitude slower for simple calculations, so I stopped looking at RDMS'es after that.

I think they solve a different problem, smaller data, data/relational integrity, data mutations. Dataframes can take shortcuts here.

If you want to do a serious benchmark, feel free to contact us. Github: https://github.com/vaexio/vaex/issues Email: (I'm easy to google).