The pictures below are worth 1000 words, so I'll limit mine. Large ISPs have been guilty for years for playing games with speeds sold vs. delivered to maximize revenue/profits and minimize costs. I'm all for profitability, but honestly earned for good service, not deceitful. They became known for doing it at the modem level by providing you with the modem/router which most of us accept. I stopped that practice now and only use my own to keep them out of it, and I know IP engineering as a former MCI Sr. Engineer.
So, I monitor .. closely. Upon Xfinity installation, I ran constant out-of-network speed tests at every step of setting up my home network in my new home to verify no configuration issues sapping speed on my end. All equip. is hardwired gigabit. Now to the pictures.
Sure enough, couple of months in, download speed is mysteriously absent. Hmm - they can't tinker with my modem, so what new trick? My usual ATT go-to test is showing <50Mb on a 250Mb service being paid for which I was getting 300Mb routinely upon installation. Ookla - same. I started calling the tech support to begin the long journey of misunderstanding and having the rep admit she only cares about keeping her job and doesn't understand the IP words I am using, but NO her employer would NEVER do anything underhanded - LOL!
Of course, I should only be using Comcast's speed test to prove I'm getting the paid-for speed, which is limited to bandwidth WITHIN their network (think about that). Sure enough, look at the 3rd pic below. Bam! Joke's on me, right? See the link in pic #3? Go to pic #4. Someone rolling out the new test, as most Comcast employees in all honesty, didn't get the secret memo and their test proves that I and plenty of others paying for more are hard-limited at 50Mb outside of Comcast's network.
Have consumers been suspecting and finding ISP shenanigans? For decades. Here's a link elsewhere on this very Xfinity site: https://forums.xfinity.com/t5/Your-Home-Network/Proof-Comcast-Throttling-Internet-Speeds/td-p/305610...
Those poor folks writing probably rarely get them solved, they just keep getting ripped off.
Run your speed tests each month, save screen shots, call billing and demand a credit for bandwidth not provided. Do this every month. Until Comcast and the rest of their competitors who all behave the same way feel it in their wallets, this behavior won't change. Don't bother with tech support - the vast majority have no idea what their employers do at the very senior engineering and finance levels and can't fix it - they'll just start the 2.5 hour grind of reboot and replace everything and then call somebody else.
Comcast folks - proof is right in front of us all. Ran these tests back to back all morning with the same results as predictable as the sunrise. You're either limiting what you want to pay outside network owners for bandwidth and/or duping customers into upgrading when unhappy with speeds, always looking for the next cleverer way to hide what you're up to, but deceit always gets uncovered eventually. Care to respond and fix, respond and deny, or remain silent?
Link to pictures: https://imgur.com/a/lUtEA26?
FWIW, can't see your pics. Since you are a new poster, they likely need to be approved by a Forum Admin. Or you may need to make a minimum number of posts.
You could try hosting them at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to them here.