CM1200 Speed drops down to 12mbps reboot fixes it for a while

[technicaljunky]

Hi all, I just bought this CM1200 and it was working fine but all of a sudden now after a while the connection drops to like 12mbps we are supposed to have gigablast (COX) service.  If we reboot the modem we will get around 900mbps but after a while it goes back to 12mbps.   Some more info is I had a motorolla surf modem before this that I had the same issue which I thought was the modem so I bought this CM1200 thinking it would fix the issue

I am not sure if the logs or settings will help but I will post them

[FURRYe38]

Your power levels are border on a bit too high.

https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router?article=24311

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.

Lots of correct and uncorrectables that should be zero. 

Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. Check for kinks and ensure fittings are correct and snug.
Be sure to power OFF the modem for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended. 
What is the brand and model of the host wifi router connected to the modem?

[Kitsap]

Be sure and install the Ookla native operating system applications on your various devices for testing (phones, computers, tablets).  The on board router applications are historically inconsistent.

The gradual decline of throughput on a re-booted coax system is usually an indication of problems with the system ground or poorly installed/corroded end fittings.

[technicaljunky]

Thanks all, the router we have is unifi dream machine

[technicaljunky]

I will have them check our lines thanks!

[technicaljunky]

I will check this all out and report back thank you!

[FURRYe38]

👍