I have a Netgear CM1200 Modem and Netgear MR60 Mesh Wifi Router. I am on a Gigabit connection.
Starting around 9/10-9/11 I started receiving notifications regarding IoT devices losing connection. When testing I could get to a speedtest and receive low ping and reasonable speeds sometimes then minutes later either not make a connection or show 0.1 Mbps Down and 35 Mbps Up.
On 9/12 After seeing that Comcast showed my modem disconnected I contacted Netgear to check if there was any troubleshooting to do. The PC was directly connected to the Modem and would still seemingly randomly get good and bad speedtests. After a full network restart and a reset on the modem it seemed to fix the issue.
That night more notifications that IoT devices couldn't connect. Next day trying to play games it wouldn't connect. Going to Discord would try to connect for a minute or two then finally connect with ping varying from 40 ms to over 200 ms . Playing a game would show anywhere from 500-1,300 ms ping then finally disconnect me for my ping. Websites and videos take 10-20 seconds to load but then seem to play fine.
I am still having the same issues today.
Router connection info: https://imgur.com/a/8fuTQ4s
The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.
I have checked my connection outiside and checked the splitters for tightness and corrosion. All of them seem fine. Neither of the two were brands you named. There is a 2 way splitter then a 5 way that feeds one line to each room in the house. There is no label on the cabels and I do not know which cable goes to which room. I will go through and disconnect each output on the splitter to see which one causes the internet to disconnect then I'll connect that one to the 2 way and see if that helps.
Other than that I called Comcast to get a tech out and they said the internet is fine and that it is my modem and that they will not send out a technician. Netgear is telling me the modem is fine. I guess I'll have to find a technician to pay to come take a look at it.
Thanks for the suggestions.