Currently no, DataFrame doesn't perform processing in parallel,
nor does it use primitive arrays (but we're thinking about it, because indeed vectorization might improve performance).
At the moment large-scale performance isn't the main priority of DataFrame. DataFrame's strengths lie in its in-memory capabilities and readable API, which make data exploration easier. For large-scale processing I'd recommend Apache Arrow (for which DataFrame has good interop), or
Apache Spark (for which there's also
interop possible)