CM1000v2 Slow Upload Speeds

[igorr]

Just installed a CM1000v2 in place of the rented xfinity modem/router, activated it, and hooked it up to my PC with a CAT8 ethernet cable. The speeds I'm getting are 700 down/5 up. My plan is 1000 down/200 up. What could be causing the 5Mbps upload speed over gigabit ethernet? Cable connection and log screenshots attached.

[Kitsap · Accepted solution]

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@igorr wrote:

Just installed a CM1000v2 in place of the rented xfinity modem/router, activated it, and hooked it up to my PC with a CAT8 ethernet cable. The speeds I'm getting are 700 down/5 up. My plan is 1000 down/200 up. What could be causing the 5Mbps upload speed over gigabit ethernet? Cable connection and log screenshots attached.

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Your CM1000v2 is not on the Xfinity list of certified modems for connection to their Next Generation Speed network.

That means you do not have access to the 100/200 Mbps upload like you had through your rented gateway.

Here is the link to the most recent list: 

https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2024.04.03%20Full%20Li...

Additional details here:

https://www.reddit.com/r/Comcast_Xfinity/wiki/knowledgebase/next-generation-internet/

[FURRYe38]

Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.
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?

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
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. 
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
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://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/

[Kitsap · Accepted solution]

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@igorr wrote:

Just installed a CM1000v2 in place of the rented xfinity modem/router, activated it, and hooked it up to my PC with a CAT8 ethernet cable. The speeds I'm getting are 700 down/5 up. My plan is 1000 down/200 up. What could be causing the 5Mbps upload speed over gigabit ethernet? Cable connection and log screenshots attached.

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Your CM1000v2 is not on the Xfinity list of certified modems for connection to their Next Generation Speed network.

That means you do not have access to the 100/200 Mbps upload like you had through your rented gateway.

Here is the link to the most recent list: 

https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2024.04.03%20Full%20Li...

Additional details here:

https://www.reddit.com/r/Comcast_Xfinity/wiki/knowledgebase/next-generation-internet/

[igorr]

My mistake, thought the recommended devices were related to the Next Gen Speed Tier.

[Kitsap]

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@igorr wrote:

My mistake, thought the recommended devices were related to the Next Gen Speed Tier.

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A number of people have found themselves in the same situation.

Please mark this issue as solved so others may benefit.