Visitor

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2 Messages

Friday, May 9th, 2025

Upload speeds are not as advertised

I recently upgraded to the Connect More plan. Before upgrading, I checked the Broadband Facts to understand what I was actually going to be paying for. The claim was 400 Mbps download and 169.62 Mbps upload. I finalized the upgrade and received a confirmation email stating that my new plan was 400 Mbps download and 150 Mbps upload. Ok, less than initially advertised, but a round number and reasonable in my opinion. Ran many speed tests across my laptop and desktop, wired and wireless, windows and linux, and in every case, the upload speed test ramps up to ~200 Mbps before quickly being throttled to 40 Mbps. The download speeds are exactly as advertised, but the rug has now completely been pulled out from under me in regards to the upload speeds. When I log in to my account on the Xfinity website, the plan details now mysteriously only claim 35 Mbps upload speed. What happened??? Every step along the way I was expecting at least 150 Mbps upload speeds, until I actually finalized the deal. I am very disappointed...

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Accepted Solution

Gold Problem Solver

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26.6K Messages

3 months ago

... My Arris S33 is not on the list despite nearly identical specs to the S34 ...

Others have pointed this out, but Comcast/Xfinity doesn't seem to care.

... Any idea if this limitation is based on any technical shortcomings of the S33?

None. Only Comcast/Xfinity knows, and they aren't saying. The few compatible retail devices are listed under the "Next Gen" heading at the top of the "All Compatible Devices" PDF linked near the bottom of https://www.xfinity.com/support/devices (at the moment that link points to https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2025.03.25 Full List of Compatible Devices.pdf, but this changes from time to time).

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

(edited)

Gold Problem Solver

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26.6K Messages

3 months ago

You need to meet all the requirements in https://forums.xfinity.com/conversations/customer-service/upload-speeds/677b01a7121aae71d76926bf?commentId=677b05b23423b47b4071a8d0&replyId=677bd66e7699a97c89069e62 to get the faster upload speeds of Next Gen/Enhanced Speed service.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

Visitor

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2 Messages

Ok, thank you, that is helpful. But that list of supported modems seems a bit arbitrary to me. My Arris S33 is not on the list despite nearly identical specs to the S34. Any idea if this limitation is based on any technical shortcomings of the S33?

Official Employee

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390 Messages

Good afternoon doubleA_doubleU. The compatible modem list is subject to change periodically. It is intended to have modems that are most compatible with our services to ensure you are getting optimum coverage. If you do need some assistance with troubleshooting we are happy to assist. 

 

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Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
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Contributor

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15 Messages

3 months ago

I have 600Mbs and have never seen it go over 150.  

New Poster

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3 Messages

3 days ago

My upload speeds have been 17 and 11 the past two days.  My plan says they should be as above [Download 400 / Upload 35].

Why would it be that awful?

[Edited: Removed Private information]

(edited)

Official Employee

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2.5K Messages

 

SueInMD That is a great question. There could be a number of reasons you are getting slower than normal speeds. Have you by chance already used the Xfinity assistant troubleshooting options? 

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Visitor

 • 

15 Messages

3 days ago

I'm using an xfinity supplied modem/router and subscribed to the 1G plan. I've never gotten over 180mb download. Getting support is impossible. Tech support number is a bot, automatically reboots modem multiple times. Does not solve the issue and impossible to talk to a human. I hope people read this before committing to xfinity internet.

Here is the plan I am paying for:

This mornings speed test:

Download Mbps 123.4
Upload Mbps 31.67

Constant buffering. Can't work from home with this connection, too unstable. If i'll never get over 200mb, why wouldn't I just downgrade until I change ISPs to save money?

Here is my original post with daily updates. I sent a direct message 2 days ago, per instruction, still no response:

https://forums.xfinity.com/conversations/your-home-network/slow-speed-receiving-150mb-on-a-1gb-circuit/688119741fc39e056ef1475b?commentId=689344e8c3884e341570dcf1

Good luck all!!

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