Gigabit Service only providing ~250mbps down

Understandable - there just isn't a single device we own that has an ethernet port.  The wifi looks good but I just ordered a dongle (good god) and I'll have something to test directly tomorrow.

For a test, does a computer / device hardwired directly to the router / gateway device with an ethernet cable have the same problem ?

With this test, we are trying to isolate this from being either a WiFi-only problem or a problem with the general connection to the Comcast system which would of course affect both. It's a good first step of troubleshooting before we proceed any further.

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@rootsup wrote:

 

Docis 3.1 modem, connected on all 32 channels

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What is the exact make and model number of the modem ?

Is there a DOCSIS 3.1 OFDM / PLC (perhaps it is labeled as being "Other" downstream channel present ?

Can we see all of the Signal stat figures please. Also post the error log entries.

Modem: NETGEAR Gigabit Cable Modem (32x8) DOCSIS 3.1 | CM1000-1AZNAS

modem status : 

https://ibb.co/KLqBnTh 

https://ibb.co/xfVJxTw

The signal stats are good. Are there any error log entries ? If so, please post them as well.

Modem doesn't have any error logs. 

O/k. What is your upload speed ?

35 - as advertised

What speed do you get with a direct connection to the CM1000 modem (no router in the mix) ?

around 360-380.

Even though the signal stats are o/k there my be noise ingress into the line(s) somewhere.

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !

Check your link @ComcastMorgan. 404 error there. (I see you fixed it).

They stated that they are using a CM1000 modem. (That too) 😏

Hi, rootsup. Frustrating to hear you're not receiving the speed you'd expect from a Gigabit level of service. One thing I'd definitely like to do is check the configuration file on the modem, to ensure it has the appropriate software to supply Gigabit. There is no reason it shouldn't, but it's worth double checking. Do you mind confirming your equipment is compatible? Please review this link here for me: https://www.xfinity.com/support/articles/requirements-to-run-xfinity-internet-service. I'm glad your modem is compatible, we need to verify that the rest of the equipment is. 🙂

Yeah - every computer in the house is compatiable, as well as the R6400 router and CM1000 modem. I'd love to check the config file - how do I go about this?

Thank you for that additional infromation, @rootsup! This is something we would need to check on our side at this time as well as have a look into the signals as EG had mentioned. Can you please send me a PM with your first and last name so we may further assist you?

To send a private message, please click my name "ComcastMichael" then select "Send a Message" on the right side.