We’ll that would support the creation of fast.com — your ISP is either lying to you (prioritizing only speedtest), or they’re punishing Netflix. Or both.

T-Mobile and others offer “HD Video” as a premium. So they cap the connection to Netflix to force 720p video.

I'm glad that at least they'd offer 720p as "non-HD", it's not too bad compared to YouTube’s 360p default in Safari iOS. Heck 720p is the limit there.

I would do a little further investigation. 1080p on Netflix is like 5MB/s. If you have a router that can give you real time feedback or maybe glasswire, that's probably how I would measure it.

Also make sure nothing else is consuming your total upstream bandwidth. With asymmetrical bandwidth, TCP acknowledgements that get choked out or buffered will limit your downstream bandwidth too.

Are you on mobile? Some mobile providers limit streaming quality and they do this by limiting bandwidth to streaming providers.

For example, Visible will never be faster than 2 Mbps to fast.com.

You’ll get faster on Speedtest.net because it doesn’t throttle non-video related sites.

I almost forgot Visible limits video streaming. My phone has an always on Wireguard VPN connection to my home which prevents Visible from limiting streaming. Just tested. From my current location, which doesn't have the best signal, with the VPN on I get 66Mbps to fast.com and with it off 2.1Mbps.

Ah this is probably the explanation. I was using my phone as a hotspot for my laptop.