2 Messages

Wed, Jan 19, 2022 5:37 PM

Slow speeds - Motorola Model MB7420

Hi, Comcast, 

For the past few months I have experienced slow speeds and frequent signal drops. I used a cable modem and separate wireless router. I have had the same tech for 10yrs without issue, though recently replaced both the cable modem and router to see if I could fix the internet speed issue. It did not. Comcast ran several virtual tests and eventually sent a tech to inspect my connection and recorded 1300mbs from the coaxial cable. The tech said my new cable modem is likely the issue, but could not confirm w/o me switching to using a Comcast cable modem via rental plan. This seems odd, so hoping a tech here can help verify this advice or share alternative ideas. Details below:

- 400mbs Comcast plan 

- Speed tests result in 10-12/mbs (performed via wireless connection) 

- Lights on cable modem show 'online' but 'ethernet' light is intermittent 

- Tested multiple ethernet cables from modem to wireless router 

- Tested 2 different cable modems and wireless routers (both are Motorola cable modems, Linksys routers) 

Accepted Solution


Gold Problem Solver


23.7K Messages

Hace 4 m

... MB7420 ... 400mbs Comcast plan ...

Please note that the MB7420 is only approved by Comcast for Internet service with "Wired Download Speed Up to 374 Mbps". Using devices on Internet speed tiers for which they are not approved tends to produce unexpected results, often speeds well below the speed you subscribe to.

You need to either switch to a lower speed plan, or upgrade your modem to one they approve for use with 400 Mbps service. Ideally you should pick a device approved for speeds a step or two above the fastest speed you expect to subscribe to in the near future, to allow for the occasional speed increases they introduce. See https://www.xfinity.com/support/devices.





2 Messages

Hace 4 m

Bruce, you genius! In my 3 conversations with Comcast, this never came up. Such a clear and logical answer to the problem. Thank you, sir! 

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