MB7621 Not Getting Rated Speeds

I know this issue has come up on the forum before, but I'm not sure I've seen the resolution. I have 800 Mbps service, but am only getting 450 Mbps. I know there is a bunch of contradictory information on the internet related to the maximum speed of this modem, but I am sure it is at least 800 Mbps.

I've had Comcast tech out to the house and cabling is getting plenty of speed into the modem itself. The computer is hardwired through a TP-Link Archer C7 router, not on WiFi. He told me the modem was probably defective. So I got a replacement from Motorola...same speeds.

From everything I have read here, the problem sounds like a configuration file issue, as in I need a different one. With the current modem user interface, it doesn't appear I can read a config file name, as others seem to have done previously based on older posts.

So I am looking for ideas on how I can get a new configuration file loaded. Is there some other support number where I can get some help?

Thanks,

Tom

Responses

NoGoodNamesLeft4Me

Contributor

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72 Messages

2 years ago

If you can, log into your MB7621 and grab screenshots of the Connection status and Event Log. Make sure to mask or cut out any PII, including any MAC addresses. I'm curious about how your channel setup is configured. Doing a quick search, I also saw conflicting information on whether this modem supports speeds over 400+ Mbps.

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trmoder

Visitor

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3 Messages

@NoGoodNamesLeft4Me Thanks for the help...

(edited)

2 years ago

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NoGoodNamesLeft4Me

Contributor

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72 Messages

Wow. That looks really good. Your Pwr (dBmV) delta is .5 (6.2 - 5.7), which is great. (Better than I have: 3.6 [11.0 - 7.4].) Your SNR is also good. Your event log is practically empty.

You have 24 256-QAM channels, and depending on where you look, that should be able to go up to 38 Mbps or 42 Mbps per channel. Even with the lower number, that's a theoretical max of 912 Mbps. I could see you only getting 450 Mbps on a 2.4 GHz wireless connection (as that's one of the numbers TP-Link quotes for that model), but I'll assume you tested using a hardwired connection to the back of the router.

2 years ago

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BruceW

Gold Problem Solver

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26.4K Messages

2 years ago

@trmoder wrote: "... contradictory information on the internet related to the maximum speed of this modem ..."

@NoGoodNamesLeft4Me wrote: "... I also saw conflicting information ..."

The only place you need to check and the only one that matters is Comcast's "device info" page at https://www.xfinity.com/support/devices/, which lists all the retail devices they support and the maximum wired download speed. For the 7621 it's "Up to 845 Mbps".

The signal stats and event log posted look fine. I wish mine looked that good!

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.

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trmoder

Visitor

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3 Messages

@BruceW I agree with you Bruce...the only place that should matter is Comcast's own web site...but, apparently, some of the customer support people within Comcast don't seem to always agree. I've had at least one tech quote me what Google says in places, rather than what their OWN website tells me!

Has anyone had success in getting Comcast to download the correct configuration file to achieve the rated speeds and, if so, how did they get that to happen? Thanks in advance for any suggestions.

(edited)

2 years ago

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CCDaniel

Problem Solver

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606 Messages

@trmoder I would like to access you account and see the configuration is correct. Can you send us a direct message.

To send a direct message:

Click "Sign In" if necessary

• Click the "Direct messaging" icon near the top right of the page

• Click the "New message" (pencil and paper) icon

• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line

• Type your message in the text area near the bottom of the window

• Press Enter to send it

I no longer work for Comcast.

2 years ago

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Your Home Network

trmoder

MB7621 Not Getting Rated Speeds

NoGoodNamesLeft4Me

trmoder

NoGoodNamesLeft4Me

BruceW

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.

trmoder

CCDaniel

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