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sylvaing
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4 Messages

Monday, June 8th, 2026 7:49 PM

1Gpbs symmetrical service capped at ~500Mpbs upload

Hello Comcast/Xfinity Support,

I’m on the 1 Gbps symmetrical Internet plan. My download speeds consistently exceed expectations (1.2 Gbps), but my upload speeds are stuck at 40-50% of this, regardless of time of day.

This used to work for weeks at a time and fixed itself after a modem restart. No longer. I have ruled out local equipment and configuration issues. 

Could you confirm the following:
- The upstream service profile I am currently provisioned with?
- Whether my Vantiva CGM601TCOM modem is fully provisioned for symmetrical multi-gig service on your network?

Tech visits have been unsuccessful. Interestingly, the last one swapped my modem for a new one. This worked for a few days before reverting to the lower speed above i.e. as if the modem once again updated itself to a downgraded speed. 

If additional testing or information is needed from my side, I am happy to provide it. 

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5 hours ago

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XfinityLinda

Official Employee

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2.6K Messages

1 month ago

Thanks for the detailed info, u/sylvaing. That’s super helpful. I can definitely see how frustrating that is, especially since it worked normally before. I’m going to check your current upstream profile and make sure your modem is fully provisioned for your symmetrical speeds. What you’re describing does sound like it could be a provisioning issue, especially with it temporarily fixing after a swap. When you get a chance, can you let me know if you’re testing hardwired, and what upload speeds you’re seeing right now? I’ll dig deeper from there, but make sure we work together to get this resolved.

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sylvaing

Visitor

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4 Messages

Yes I am testing hardwired. Upload has averaged about 500. 

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1 month ago

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XfinityRichard

Official Employee

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3.4K Messages

Thank you, @sylvaing for that additional information. Let's get your account pulled up, so we can look deeper into this for you. Can you please DM me your full first and last name along with your full service address so that I can assist you further.

 

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1 month ago

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sylvaing

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4 Messages

I have responded.......

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1 month ago

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sylvaing

Visitor

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4 Messages

Update on this: this is still an issue and I still suspect a profile issue. What has become clear is that when your support staff resets/reboots the gateway, it works as expected for some time before falling back to 50% upload speed. I also used to be able to do this via the Xfinity Assistant i.e. it would detect that something was wrong, restart the gateway and all was good for a few weeks. Now when a support person does a restart, speeds are symmetric for a couple of weeks at most. 

I know we have discussed sending someone to my home but what can they realistically do to ensure I get and maintain the right profile? They have come here and swapped the modem and that didn't do anything. 

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5 hours ago

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