@steveits Packages installed ? NONE.
CPU usage: about 50% when not doing the test (and otherwise no activity) No change when the test begins and ends.
After the test has ended however, CPU Usage climbs from about 50% to 98% for 5 seconds, then it returns to its normal 50%.
At the end of the day, it seems to me the SG-1000 may well be the bandwidth limiting factor. Should this be the case, then I will not change anything as I do no need such a high bandwidth anyway.
Thank you for your kind assistance.