Re: CM1200 speed issue with Xfinity Gigabit service

FURRYe38 · ‎2020-08-27

Somone at XF just wants you to buy something else or use there modem. Someone is not being honest at XF with you. The CM1200 is WELL capable of 1Gb ISP speeds.

https://community.netgear.com/t5/Cable-Modems-Routers/CM1200-slows-down-after-24-48-hours-of-uptime-...

There has been a recent update as aswell that fixes LAG enabled modems with slowdown on 1Gb services. Be sure the modems FW has been updated from the ISP. I believe XF and CC has this new version out now.

@persiancowboy wrote:
I've had the same problem and after many hours of Xfinity tech support, they reached the conclusion that the Netgear modem is not capable of delivering the gigabyte speed that they claim on the package.

jallanbryant940 · ‎2020-09-15

The issue here is that Comcast has proprietary provision over the Firmware Version. Comcast recently Updated

their Platform that locked out any third party modems. Having done so it forces their customers to lease their

devices to obtain the top tier Downstream. I have spent the last two weeks Diagnosing and Troubleshooting with My

Systems. I had maintained all lines from the Drop to My modem direct with no spliters. I had done a direct wired

connection from the modem to my PC. Initially I had a Gigabyte Modem form a Different Manufacturer That

was working perfectly. I was only purchasing 600mbps and experiencing less than 100mbps of drop.

Then the issues started one morning last week. Pages wouldn't load. Speedtests did not flow downstream, but

up stream was still working at up almost 30mbps. A comcast tech convinced me today that is a way to have that

firmware update. I have yet to try that method, but I am starting over with a completely different Modem.

I will attempt at updating the firmware, Especially if it is not Version 6.01.06. I will have to make the attempt before

Comcast/xfinity Provisions the Modem for their Network. Thusly My reason for starting with a New Modem.

When Netgear distributed these Top Tier Modems they were flashed with Versions that Comcast/xfinity deployed

when the Modems were manufactured and then placed in the Consumers Market. Xfinity has since changed version

again for their Service. When the speed drops considerably it forces you to lease their Modem just so you can have

Internet. Examine Netgears Firmware Page to confirm what Version Xfinity now deploys and compare it to what

is Flashed on Your device. If you try to go into admin tool on Your Modem after Xfinity has provisioned Your Modem

You may not be able to access Admin Tools on the Modem. I believe Comcast/Xfinity software excludes the Users

abilty to access Admin Tools on the Modem. There is supposed to be a feature in Admin Tools that allows the User

to Update the firmware. Again the Firmware comes fromXfinity. Netgear will not provide the User with it

because it's deployed by Xfinity.....

lazybone · ‎2020-09-15

Solved my issue by dumping my cm1200 and switching over to the Motorola MB6800 getting my gigabit speeds wired and averaging over 500mbps through wifi. At one point I was thinking xfinity was capping me but I was wrong!

FURRYe38 · ‎2020-09-16

The CM1200 is WELL capable of 1Gb ISP speeds.

https://community.netgear.com/t5/Cable-Modems-Routers/CM1200-slows-down-after-24-48-hours-of-uptime-...

There has been a recent update as aswell that fixes LAG enabled modems with slowdown on 1Gb services. Be sure the modems FW has been updated from the ISP. I believe XF and CC has this new version out now.

@lazybone wrote:
Solved my issue by dumping my cm1200 and switching over to the Motorola MB6800 getting my gigabit speeds wired and averaging over 500mbps through wifi. At one point I was thinking xfinity was capping me but I was wrong!

FURRYe38 · ‎2020-09-16

You'll need to talk to someone or escalated support regarding your modem on CC/XF network. They should be able to provision the modem so it works right on there system. Others have received the newer FW update that fixes the slow down when LAG is enabled. If your modem has not recieved this update, ask the escalated support about it.

Have the ISP check the signal and line quality UP to the modem.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.

@jallanbryant940 wrote:
The issue here is that Comcast has proprietary provision over the Firmware Version. Comcast recently Updated
their Platform that locked out any third party modems. Having done so it forces their customers to lease their
devices to obtain the top tier Downstream. I have spent the last two weeks Diagnosing and Troubleshooting with My
Systems. I had maintained all lines from the Drop to My modem direct with no spliters. I had done a direct wired
connection from the modem to my PC. Initially I had a Gigabyte Modem form a Different Manufacturer That
was working perfectly. I was only purchasing 600mbps and experiencing less than 100mbps of drop.
Then the issues started one morning last week. Pages wouldn't load. Speedtests did not flow downstream, but
up stream was still working at up almost 30mbps. A comcast tech convinced me today that is a way to have that
firmware update. I have yet to try that method, but I am starting over with a completely different Modem.
I will attempt at updating the firmware, Especially if it is not Version 6.01.06. I will have to make the attempt before
Comcast/xfinity Provisions the Modem for their Network. Thusly My reason for starting with a New Modem.
When Netgear distributed these Top Tier Modems they were flashed with Versions that Comcast/xfinity deployed
when the Modems were manufactured and then placed in the Consumers Market. Xfinity has since changed version
again for their Service. When the speed drops considerably it forces you to lease their Modem just so you can have
Internet. Examine Netgears Firmware Page to confirm what Version Xfinity now deploys and compare it to what
is Flashed on Your device. If you try to go into admin tool on Your Modem after Xfinity has provisioned Your Modem
You may not be able to access Admin Tools on the Modem. I believe Comcast/Xfinity software excludes the Users
abilty to access Admin Tools on the Modem. There is supposed to be a feature in Admin Tools that allows the User
to Update the firmware. Again the Firmware comes fromXfinity. Netgear will not provide the User with it
because it's deployed by Xfinity.....