pony is compiled to native code, and to highly optimized code. beam is just interpreted. even if most of the time the code has to wait, it has to wait much less. that's why pony can beat C++ with OpenMP in comparable tasks.

It's garbage collector is superior, having to do much less work than in beam.

The data workload for each thread is much smaller. objects are tiny, messages are mostly referenced (shared) and not copied.

erlang does more. it already supports distributed actors, so there's a little overhead also.