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Sunday, February 2nd, 2025 8:40 PM

Not Getting Advertised Upload Speeds

Hello!

I had an 8 year old modem and router setup, and I was paying for the 800 down, 20 up plan. With my old modem, I was not getting the download speed that I was paying for (usually around 250ish down and 22ish up). Yesterday, I purchased a new modem (Arris Enterprises S33 DOCSIS 3.1 Cable Modem) and router (ASUS RT-AX5400), and after getting everything setup, I was getting around 900 down and 22ish up. Great!

I then saw that I could upgrade my speed to the 1 gig down and 150 up for effectively 20 bucks less per month, so naturally I hopped on that bandwagon. I received a confirmation email where it states the whole "up to 1 gig down and up to 150 up". Now, I understand "up to", but I'm still only getting the 20 up that I was originally getting with (a) my old equipment and (b) my old plan. I wasn't expecting to get the 150 up, but if I got around half of that I would have been happy. I tried resetting my router and modem after upgrading my speed, but that didn't help.

There is an Xfinity store by my house, so I swung on over there today to talk with them to see if they had any ideas. They showed me that my account still showed my old modem and they said that's likely why; I guess the system was just sending the old amount signal, so they deleted my old modem off of my account so that only my new one remained. They told me to restart my modem and router when I got home and see if that worked.

It did not.

I just have no idea what else could be going on. Any help here would be greatly appreciated! Attached below are my email confirmation as well as my most recent speed test.

Accepted Solution

Gold Problem Solver

 • 

26.2K Messages

13 days ago

.. Arris Enterprises S33 ... still only getting the 20 up ...

Realize that although Comcast calls some devices "Compatible" and some "Recommended", for all but a few devices those designations only mean "compatible/recommended for use with their Internet service", and not necessarily approved for the upload speeds introduced in 2023.

The S33 is not compatible with those speeds. Only a few retail devices are. See the "Next Gen" list 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/2024.09.18%20Full%20List%20of%20Compatible%20Devices.pdf, but this changes from time to time).

For faster upload you need one of Comcast's newer rental gateways (XB6, XB7, XB8) or one of the few retail devices shown in the "Next Gen Speed Tier" group at the top of the "All Compatible Devices" PDF:

  • Hitron Technologies CODA or CODA56
  • Netgear CM2500, CM3000, or CBR750
  • ARRIS/Surfboard G20, G34, G36, G54, or S34
  • Ubiquiti UCI 

Comcast/Xfinity could make all of this much simpler and clearer, but they have chosen not to do so.

For additional requirements for faster upload see https://forums.xfinity.com/conversations/customer-service/upload-speeds/677b01a7121aae71d76926bf?commentId=677b05b23423b47b4071a8d0&replyId=677bd66e7699a97c89069e62

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.

3 Messages

Fantastic, thanks for the info!

Agreed that the wording is very annoying, doubly so since the modem that I purchased is one that Xfinity recommended in an email to me... Oh well. I guess I'll just live with the 20 mbps upload.

Thanks again!

3 Messages

I just wanted to thank you again Bruce. I decided to just go get the Arris S34 and return my S33 (they were basically the same price, which is wild) and I'm now getting 180 upload. You're the MVP!

2 Messages

I recently replaced my 10 year old Netgear modem in order to get the faster speeds that Xfinity has been emailing me about. I have an approved modem, the Hitron CODA56, I live in downtown Seattle with Xfinity's upgraded network (at least that what their emails were telling me), I have chatted with 3 techs, phone conversation with 2 techs, and 1 in-home visit to determine that I am getting perfect signal strength and I am still stuck at 20Mbs upload speed.

How do I get this fixed as nobody seems to know why my upload speeds are stuck at 20Mbs when I have the service (1000 down / 150 up), a compatible modem, and my work from home network is mostly 2.5Gb & 10Gb ethernet?

Any pointers will be much appreciated!

Thanks,

Justin

(edited)

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