The high reduction cost is deliberate. Reductions in BEAM are an arbitrary value that certain operations in ERTS assigned. Sending to a remote node has a high reduction cost, which means that the more sends you do, the more your process has to be rescheduled to do remote sends. We worked around this with manifold, by limiting the number of remote sends we do to fan-out messages, and transforming them into local sends on the receiving nodes, which has a much cheaper "reduction" cost.