Same problem - gigabit internet, everything has been working fine last year up until beginning of March. Finally got a hold of Customer Support last week, and the first tech support reported, that after we power cycle the router / reboot, they were going to upload something into the router and do some changes. That didn't fix the issue and i got disconnected from chat and had to start over. Contacted a second tech and all they said was there was scheduled maintence in our area and pawned it off as that. Maintenence has been past and still experiencing the same issue you are having as well, Ping MS is all over the place from 21 to 420ms, and a lot of request time out. They were trying to put the blame on my router, saying it's not approved, but it's literally on their website Netgear C7800 and had it approved by tech, and onsite tech that set it up. literally doesn't help that they say they have a "ticket/reference numbers" for their chat techs, but everytime i get a hold of someone after hoours of waiting, no one knows a thing about it and i have to start over from the beginning.
Background : I work as IT for a company and work remote from home.
I've already gone through all the pinned post diagnosing and nothing has worked. Running various tracerts and Ping tests throughout different times of the day and night, all yield the same result.
Also, thought I add some Logs and Upstream/Downstream info as I have a feeling it might help.
Modem/Router is Netgear C7800 setup by Xfinity Tech, I own the router.
Can't see your pics. Since you are a new poster, they need to be approved by a Forum Admin. That could take some time. In the interim, 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.
The downstream power is too high. Is there an amplifier on the coax line leading to the modem ? If so, try removing it. If not, try using a 3 dB signal attenuator pad like this one on the back of the modem;
You could try a 6 dB one as well. Not certain that this is the direct cause of the problem. YMMV. Good luck !
From what i remember of the layout, There's a Coax line that goes from the box in front of our house, directly to the router. From there, everything is ethernet corded out tot he house with one cable, no addtional splitters or boxes.
I don't see any additional adapters tied in to the coax line and unfortunately, i can't check outside in the box.
O/k try the attenuators or book a tech to come out and investigate. Good luck !
Tested 3DB and 6DB attenuators, both options failed, still getting dropped packets and 80% reduction in speed from my gigabit. Neighbor is also experiencing the same issue on XB router same service.