Again, very helpful. This is getting very interesting. So I'm getting the impression that the reason I benefit from multi-threaded demand (e.g., two Roku streams) is unique to the type of network my ISP operates (wireless). I just learned Chrome supports 6 parallel TCP connections, so for general browsing, it seems unlikely I would see much difference between 3 Mbps and 5 Mbps single-thread performance, especially given that browsing is very bursty. More importantly, with up to six concurrent connections working, my poor single thread performance shouldn't impose much of a limitation for browsing.
OTOH, I'm often clicking on links that open large image or PDF files (sometimes tens of MB's). My assumption is that's handled as a single connection. However, I just found this from a 2018 article on parallel downloading: "Google Chrome can establish multiple connections to download a single file in parts." (emphasis added; if you Google this quote, you'll get lots of hits). If I'm understanding this correctly, it raises the question why the TMN single-thread test isn't split across multiple connections. Is this something TMN can control, or maybe I need to do some testing to see if Chrome really does use multiple connections when downloading a single file. But I'll have to find an app like Resource Monitor for my Linux OS that shows the number of TCP connections open.
ginahoy got a reaction from Sean in why the big difference for multithread test results?