I've now just tried with Python 3.7.1 and the same problem persists, so I'll now try to use a second thread for the console app.
PS For these CPU-intensive apps which use multiprocessing to use all the CPUs, compared with Python 3.4, 3.6 is 13% faster, and 3.7 is 33% faster! -- https://mail.python.org/mailman/listinfo/python-list
