Question Comcast CGM433 - Replacing With Motorola Modem

[RhoXS]

In another thread I discussed a now fully resolved problem placing the Comcast CGM433 in Bridge mode and using an external router. The external router is a TP-Link triband AC-5400. I immediately noticed the external router provided a very noticeable increase in internet speed (maybe actually just a significant decrease in latency) on my Ethernet connected desktop, even though the speeds I am now seeing per speed tests are still sometimes less than 25% of the advertised 1200 GPS for the Comcast Gigabit-Extra service. So, now I am thinking about replacing the Comcast CGM433 with a new modem like the Motorola MB8611 DOCIS 3.1 Multi-Gig Cable Modem. I would like to get opinions about the following before I spend over $200 on this thing.

-Am I likely to significantly increase internet speed by replacing the Comcast CGM433 with the Motorola modem I referenced above?

-Am I assuming correctly I have to notify Comcast to recognize my new own modem before it will work? This modem is advertised as being "Certified for Comcast Xfinity..." but I do not know if that means it is a plug & Play replacement for the Comcast provided device.

I do not know if it matters but Comcast provides fiber to a powered module in my service drop box on an outside wall with coax coming into the house.

Thank you.

 

[Tech Junky]

MB8611

I used the 8600 and bonded 2 ports for years. They're a worthwhile investment but, AC wifi won't max it out on a single client. You would need AX to do that and an AX411 card on the client side and that will max out at 1.7gbps.

 

[RhoXS]

AC wifi won't max it out on a single client.

WiFi speed is not an issue for me as I do not use WiFi for anything other than phones, iPads, and other minimal WiFi devices like thermostats, door bell cam, garage door openers, etc. All the big hitter data hungry devices, like the smart TVs, are all hard wired Ethernet. I converted all the TVs to Ethernet a few years ago when I finally ran out of patience with freezing, stuttering etc. The Ethernet connections completely eliminated all the issues but I recognize the TV problems may have been due to the crappy Comcast modem/router WiFi implementation. The major item causing me to notice internet speed is my Ethernet connected desktop computer so WiFi maxing out on a single client is not a concern.

 

[lantis3]

Couldn't find Comcast CGM433 via Google , only found Technicolor CGM4331. Is it the one? It's DOCSIS 3.1, so in theory it will go over 1Gbps (up to 10Gbps, https://en.wikipedia.org/wiki/DOCSIS) if your subscription plan that's over 1Gbps. (Yours is 1.2Gbps?)

"speed tests are still sometimes less than 25% " What's the speed test results most of the time then? And what's your fastest NIC for your PC? Do you have a 2.5Gbps NIC?

================

OK. Your TP-Link has 1× Gigabit WAN Port and 4× Gigabit LAN Ports. That limit your internet speed to 1Gbps top. You need to get a router that has WAN/LAN ports that's 2.5Gbps.

Technicolor CGM4331 has an ethernet port with orange line that's 2.5Gbps, all other ports are only 1Gbps. You then connect new router's 2.5G WAN ports to modem gateway's 2.5Gbps port.

 

[Tech Junky]

The major item causing me to notice internet speed is my Ethernet connected desktop computer so WiFi maxing out on a single client is not a concern.

Well, there's no point going with a 2.5gbps modem if you don't upgrade to a router that has 2.5 ports as well. Hell, when I first did gig my router couldn't even break 300mbps wired. Not all routers will have full bandwidth if you're not careful with your choices of hardware. I tried a few of them and ended up with a Netgear R7800 for awhile before just building my own setup instead due to all of the glitchy consumer firmware updates. Most current routers shouldn't have a problem though but still something to dig into before buying one or at least use Amazon for easy returns if it doesn't meet your standards.

 

[RhoXS]

The label on the bottom of the white modem reads "PN: CGM4331COM". Its my error for inadvertently truncating the complete number. With the full part number it readily comes up in Google and even ebay.

I perceive Comcast provided equipment is OK but overall it never represents stellar performance. An example of this just occurred when I put the subject Gateway/Modem in Bridge mode and started using an external router. It was immediately obvious internet response was very noticeably faster, probably due to reduced latency, not so much because the data transfer rates have changed. Nevertheless, the now almost instant response time of my Ethernet connected PC is very satisfying. Additionally, the WiFi signal on both bands is much stronger and consistent throughout my house now, than previously with the Comcast CGM4331COM. This is especially important because some devices (e.g. the electronic door look) no longer periodically looses WiFi connectivity.

In any case, I would still appreciate thoughts on the following two questions:

-Am I likely to see some increased internet speed and/or reduced latency by replacing the Comcast CGM4331COM with the Motorola MB8611 DOCIS 3.1 modem I referenced above?

-Am I assuming correctly I have to notify Comcast to recognize my new Motorola modem before it will work? This modem is advertised as being "Certified for Comcast Xfinity..." but I do not know if that means it is a plug & Play replacement for the Comcast provided device.

Thank you.

 

[Tech Junky]

-Am I likely to see some increased internet speed and/or reduced latency by replacing the Comcast CGM4331COM with the Motorola MB8611 DOCIS 3.1 modem I referenced above?

Maybe. The other thing about their CPE is they have hotspots enabled for other users that are subscribers as well.

-Am I assuming correctly I have to notify Comcast to recognize my new Motorola modem before it will work? This modem is advertised as being "Certified for Comcast Xfinity..." but I do not know if that means it is a plug & Play replacement for the Comcast provided device.

All you need to do is hookup a device directly and go through the walled garden sign in and it will add it to your account for use. Otherwise you can call and add the MAC to your account beforehand but, the sign in option is quicker.

 

[RhoXS]

"... they have hotspots enabled for other users that are subscribers as well." - I certainly know what a hot-spot is but I do not have a clue how this impacts me. Please explain.

What is "the walled garden sign in"? Can I assume that is in a setup dialog in the Motorola modem I access via a IP address?

Thanks for your response and especially being patient with my questions.

 

[Tech Junky]

"... they have hotspots enabled for other users that are subscribers as well." - I certainly know what a hot-spot is but I do not have a clue how this impacts me. Please explain.

The CPE has additional SSUDs being broadcast for the public to use as a WIFI connection.

What is "the walled garden sign in"? Can I assume that is in a setup dialog in the Motorola modem I access via a IP address?

When you hook up a new modem and it syncs to the backend and goes online you get a page prompt on a browser when you connect a PC to it directly and you simply sign in to your CC account and it adds the modem to the account and reboots and you're online.

The non-CC modems typically have a dashboard available for stats and sometimes more stuff you can configure @ http://192.168.100.1 login typically is "admin/motorola"

 

[Fallen Kell]

As already said, for the comcast ready equipment, you should be able to self service add it to your account without needing to call. Just be ready to initially directly connect to the modem from a wired PC (not through a router) and know your comcast admin account email and password. Otherwise you can call them up and do it over the phone, but be sure to have the mac address and other ID numbers from the modem ready.

As for performance, your router needs to be up to the task. I use a PC running PFSense connected via a 40gbit trunk port to my network core. It is just routing between 2 VLANs over that single link (the comcast modem is connected via 2x1gbit CAT6 to my Brocade ICX6610 with those ports set to the "WAN" VLAN, which is also set on the 40gbit port used by the PFSence along with the "LAN" VLAN). If and when comcast has a modem with SFP+ or 10gbase-t, I can easily just swap out the modem and connect it to one of those ports on the 6610 and just tag it as the "WAN" VLAN without needed to make any other kind of change.