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New to xfinty and I want to buy my own modem. I have questions.

New Poster

New to xfinty and I want to buy my own modem. I have questions.

I have just contracted with xfinity for internet and tv services. I have not yet activated my service, but I already know that I want to replace the provided (rented) gateway with one of my own. I signed up for Exteme Pro 400Mbps speed. I used the xfinity equipment checker to see what my options are. From there I have narrowed it down to a few potential choices in my preferred pricerange:


Motorola MB7621  24x8 channel

Netgear CM600  24x8

Arris SB6190  32x8

Netgear CM700  32x8


All of the above modems are around $100 and would seem to meet my requirements. Does anyone have any feedback regarding quality, customer support, known issues, etc? I have read countless reviews on amazon but there really doesn't seem to be a consensus choice. I've searched individual models on this forum as well and I am no closer to making a decision.


What is the benefit of DOCIS 3.1 over 3.0? 24 channels should accommodate the 400Mbps advertised speed (24x24=600), but are 32 channels better? Also, I understand that speeds will be "up to" 400Mbps and I am not all that bothered if they are lower as long as everything is reasonably fast and stable. I presume that the 400Mbps speed is hard wired and that I should expect less once a wifi router is in the equation. Is this ture?


The next price point (~$150) seems to offer a bit more in terms of specs, but I'm not sure if any of it is relevant for me.


Netgear CM1000  32x8  DOCIS 3.1

Arris SB8200 .  32x8 3.1

Motorola MB8600 32x8 3.1


Thanks in advance for any/all advice.



Re: New to xfinty and I want to buy my own modem. I have questions.

DOCSIS 3.1 isn't needed unless you plan to subscribe to their gigabit speed tier. 32 channels would be more reliable than 24 especially at times of peak traffic congestion. The 6190 is known to be problematic (Puma 6 chipset issue). I personally would recommend the Netgear CM700 !

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New Poster

Re: New to xfinty and I want to buy my own modem. I have questions.

Thank you for that. I forgot to rule out the Puma 6 equipped models.


I just noticed Costco has the Netgear CM1100 on sale for just a bit more than the CM700. I'll probably go with one of these two. 


I may be back later with questions on setup, but hopefully I won't need it!