[zx10guy]

Run a continuous ping test where you're pinging google.com and the internal IP of your router at the same time. See if you're getting any dropped packets at the same time on both ping tests.

I was having this issue with Mediacrap at my vacation home. Couldn't stream anything. VPN connectivity when I worked remotely was crap. Even web pages were starting to load slowly. Mediacrap didn't even argue with me when I finally had the time to work with an onsite tech. The rep could see all the errors on their end. A tech was sent out. Found the TV block they put to prevent me from stealing basic cable was sopping wet. The block was removed which made the line signal better but it wasn't the sole issue.

For what ever reason, the coax line from the exterior DMARC of my home to the structured wiring cabinet went bad. The tech tested that run and the signal to noise ratio was unacceptable even though when I had service first established everything was fine. No work on my house that could have caused that issue. Fortunately, the sub that ran the structured wiring did the smart thing and ran an extra run of RG6. We tested that run and everything test fine. So I switched over to that line and it's been good since...except the typical Mediacrap performance issues.