All the approaches run code on the remote machine, but which process they do it in is different:

• a named GenServer will handle the message in its single process
• :rpc will perform the specified apply in the RPC server process. There’s one of these per node
• a remote Task.Supervisor will handle the “start a task” request in its single process, which starts a separate process where the Task does its work

The difference is easier to think about if you imagine the “actual work” part of each of these takes a while - imagine Process.sleep(2000) as a stand-in. If three requests in close succession are sent to the three approaches, here’s what happens:

• the GenServer and :rpc approach both take slightly more than 3x the time of one “actual work” step, because they handle messages one-at-a-time
• the Task.Supervisor approach will take slightly more than 1x the time of an “actual work” step, as it handles messages by starting a process for each