I would go with http://cutycapt.sourceforge.net/ old but still small and useful. Source: almost 2 years ago

Hello! Ever since moving into a new house, I've haven't been getting the speeds I've expecting. Specifically, videos and websites will fail to load or load extremely slowly most of the time. The odd thing is, when running a speed test (tested using both testmy.net and speedtest.net on Firefox with my laptop wired via ethernet), I'll get 5 mbs down on the first test, 100 mbs on the second test, then back down to 15... Source: 7 months ago

Another speed test site is https://testmy.net The site claims superior accuracy (which I can't confirm but probably someone here can evaluate one way or the other). The site offers a number of test options and other amenities. I'll have to try these other sites to see how they compare. - Source: Hacker News / 8 months ago

T-Mobile - 5G WI-FI decently priced... If it only worked! Below I'll post my results from a few hours of a test I did today using Testmy.net. This is an every day occurrence. You could be watching a YouTube video at a nice 1080p60, but then it'll switch to buffering for about 5-15 minutes on average. Or you can watch it on 144p or 240p "with some buffering". The longest downtime was for about 45 minutes to date. Source: 12 months ago

Go to testmy.net and test it, what are the scores there? Source: about 1 year ago

I prefer using TestMy Which one is better? Your guess is as good as mine.... Source: about 1 year ago