U

Visitor

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3 Messages

Mon, Jul 11, 2022 7:22 PM

Modem compatibility with 900 Mbps plan

Online there is conflicting information about the Motorola MB7621 compatibility with the 900 Mbps plan. Can someone clarify if this modem will "handle" this speed? Thanks.

Accepted Solution

BruceW

Gold Problem Solver

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24K Messages

3 m ago

... If it just slows speed a little ...

The usual result of using a modem that's not approved for a speed tier is not "just slows speed a little", it's more like "slows speed a lot". AFAIK Comcast has never said just how they handle this situation, but users have reported 1/2 subscribed speed or even less. If you proceed please post what speeds you actually receive with this combination.

BruceW

Gold Problem Solver

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24K Messages

3 m ago

Online there is conflicting information about the Motorola MB7621 compatibility with the 900 Mbps plan. Can someone clarify if this modem will "handle" this speed? Thanks.

https://www.xfinity.com/support/devices says the 7621 is approved for "Wired Download Speed Up to 845 Mbps", so not quite enough for 900 Mbps.

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Visitor

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3 Messages

3 m ago

Thanks. Yes, I saw that. The 845 is close enough to 900. My concern was that switching to the 900 plan without changing to a new modem might in some way make internet access suddenly impossible, for example, because of being DOCSIS 3.0 instead of 3.1. If it just slows speed a little from its theoretical 900 Mbps max, I can live with that or buy a new modem at my leisure. 

Official Employee

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110 Messages

Hey there! Thanks for reaching out here in our community. We indeed rate this particular make and model for up to 845Mbps download, (https://comca.st/3z5H1Mp), keeping in mind this is using an Ethernet connection. For a wireless connection, it is expected to get half of the download that you subscribe to and closer to the speeds with a wired connection. 

 

What happens is that when you use an incompatible modem for a faster speed tier, the modem will default to using an even slower configuration file, so you will get even slower speeds than before. You need to use a compatible device. You can search for one at that link that I supplied.

 

We can not say for certain that your speeds will be lower than 845Mbps until we test your speeds with the new service levels. 

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EG

Expert

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95.8K Messages

@XfinityErika​ wrote: 

 

"What happens is that when you use an incompatible modem for a faster speed tier, the modem will default to using an even slower configuration file, so you will get even slower speeds than before. You need to use a compatible device."

Hmmmm.... Sounds like my macro, verbatim. Did you steal that from me ??? 😮

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Visitor

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3 Messages

2 m ago

I appreciate the responses and I'll post results if I upgrade, but am likely to go to only 600 instead of 900Mbps.

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