His workload is embarrassingly parallel[0] and the message-passing between the Pi is basically free since the results are so small to send-back (and there's not

His workload is embarrassingly parallel[0] and the message-passing between the Pi is basically free since the results are so small to send-back (and there's nothing to send to each node on startup). He's effectively doing a trivial map-reduce [1]. He could probably get even better than the Pi cluster by using a (single) GPU. [0] https://en.wikipedia.org/wiki/Embarrassingly_parallel https://en.wikipedia.org/wiki/Embarrassingly_parallel [1] https://en.wikipedia.org/wiki/MapReduce https://en.wikipedia.org/wiki/MapReduce