So … today I decided to run speed tests on my Internet again …
The faster numbers on December 10 are for the 5 Ghz Wi-Fi channel and the slower for the 2.4 GHz Wi-Fi channel. The 5 Ghz Wi-Fi channel is fast enough to keep up with the native cable modem speed, the 2.4 GHz channel … not so much. I think I knew that, but had not paid attention as I always connect via the 5 GHz channel.
My son confirms that direct wired connection is running at full speed as well.
I am definitely getting a “performance discrepancy” with Comcast that varies throughout the day. Does this reflect bandwidth congestion from other users? Probably.
Will retry the upload now.