Upload speeds very slow. Went from 11 up to 5 up after upgrading.

Question

I recently upgrade my plan from 300 mbs to the 1 gigabit. Immediatly after activating my new plan the upload speeds went from 11 mbs to 5 mbs.

The download speeds did increase to around 560 mbs down, but why would my upload suddenly be cut in more than half?

I am currently using an Arris SB6183 which caps download speed at 680 mbs but the upload is still well within the modems capabilities. I have tried connecting directly from the modem as well as going through my ASUS AC3100.

I have a new modem coming in (Arris sb6190) that will support both 1 gigabit download speed as well as 200 mbs upload.

Is there any way I can solve my terrible upload speeds in the meantime?

EG · Answer

You need to use a DOCSIS 3.1 capable modem for gigabit speed, otherwise a DOCSIS 3.0 modem will default to using a slower speed configuration file. That's why your upload speed drops to a slower speed tier.

EG · Answer

You can't use an SB6190 either. It's only DOCSIS 3.0 capable.

Stuffs · Answer

Docsis 3.0 is capable of upload speeds up to 124 mbs. Not to mention that before upgrading my down speed I was getting 12 mbs up. I should at least be getting that much.  Really I should be getting the 35 mbs up I'm paying for. This is well in the range of 3.0 up speeds.

Stuffs · Answer

I was using this same modem and getting higher upload speeds than I am now.

The current config file it is using is clearly capable of at least 12 up because I was getting that.

No equipment changes have occured.

So why would it require docsis 3.1 to get at least what I was previously getting?

A friend uses this same modem on another internet provider with gigabit speed and gets 100 mb up.

So is this a Comcast issue?

EG · Answer

https://www.xfinity.com/hub/internet/what-is-gigabit-internet

EG · Answer

First. There is no such thing as 100 Mbps upload speed with DOCSIS cable systems yet.

Did you read the part of my comment that said if a DOCSIS 3.O modem is used when trying to upgrade to the gigabit speed tier, the modem defaults to using a slower speed configuration file ? Perhaps even slower than the original. Including the upload speed. You are entitled to believe what you like..... I suggest that you do some research please.

EG · Answer

Guess you don't understand... Sorry... I stand by my comments. Good luck !

strega7 · Answer

I just browsed Comcast's compatibility page for my address (since I don't know yours) and every modem listed as compatible with Gigabit was Docsis 3.1, so I think EG is right.

Stuffs · Answer

Unfortunatly this is only addressing down speed. My down speed is not the concern. I'm fully aware of the issue with down speed. Even the compatability list on Xfinity doesn't account for upload speeds only down speeds. It seems the reason they don't list the SB6190 is that it supports up to 1 gigabit and the requirement according to the compatability selector is to choose a modem that is higher than your current teir. This wouldn't be higher, it would be equal. But alas none of this addresses upload speeds. My download speeds are fine.

EG · Answer

https://forums.xfinity.com/t5/Your-Home-Network/Gigabit-speed-troubleshooting-video/m-p/3310454#M316654 Jump to 2 minutes and 30 seconds if you like.

Your Home Network

Stuffs

Upload speeds very slow. Went from 11 up to 5 up after upgrading.

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strega7

Stuffs

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