mrbq1108's profile
Conversation Starter
1st Kudo
1st Best Answer

New Poster


15 Messages

Thu, May 28, 2020 7:00 PM

Arris SB8200 - speed and stablity issues - 1000mbs speed but cannot get past 350mbs (links updated)

I have an Arris SB8200 modem, a Netgear Nighthawk X6S router and a 10/100/1000 ethernet card. My PC is hardwired via Cat5e directly to router. I have connected my PC directly to the modem and also had trouble.


It seems like a lot of folks are having issues with their Arris SB8200 modem and the 1GB offering. My old DOCSIS 3.0 router/modem combo clocked around 600mbs on the Extreme Pro; now with a brand new Arris SB8200 and the 1gb offering, my comp clocks 400mbs on a good day.


An Xfinity  tech came out to my home and cleaned up some splitter issues; however, it did not fix much. The tech ran a test directly off the coax and showed me speeds >1gb. He had me run a speed test from my PC and appeared quite puzzled by the results. He advised to wait a week or two for the modem to be provisioned correctly, and that did not make much sense to me.


I've contacted Arris and they advised it was an ISP provisioning/configuration issue


Here is a response from Arris:

"We have encountered that the possible reason of the issue you're experiencing with your internet performance, is due to the lack of power in the Upstream signal. The acceptable range is within 45 dBmV and 51 dBmV, and as you can see, they are all below the minimum. Please contact the service operator in order to re-provision the service and adjust the signal to the acceptable. Once done, your internet's performance should go back to normal."


Here is a snapshot of a recent speed test and modem data:



Does anyone know what the problem is? Xfinity support pros, can you all fix the issue?


Thanks for your time.


Accepted Solution


New Poster


15 Messages

1 y ago

I dropped my service to 600mbs and now clock >700mbs on my SB8200 and Netgear X6S. There is defintely a network configuration issue; before the downgrade I could only get 350mbs.


We even tried and Xfinity modem and had issues. I was able to pull 950mbs via the desktop app; however, it was never reliable and Firefox could never clock it. Do yourself a favor and save the money.


Download the Ookla app too, as there is a difference between Firefox and the desktop app.


New to the Community?

Start Here