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Forum Discussion
CM1200 speed issue with Xfinity Gigabit service
Hello, I have gigabit service with Xfinity, and I did a speed test and pulled 950mbs, instead of renting the XB6 I purchased the CM1200, now my speeds are ~450MBps. I did not configurations on th...
Just be cause the one modem on the line works and the other doesn't, doesn't mean that the signal on the coax line is good for the CM1200. Something to be sure you have the ISP check while the CM modem is online. They can see whats going on...
LAG (Link Aggregation) should be disabled, just check for this on the CM modem.
So when your Laptop is directly connected to the CM modem, it's not seeing anything near 900Mbps? Correct?
Try swapping to the 2nd port on the back.
I think others do, i know this as one issue with the CM1200 that users have reported is that after enabled LAG on the 1200, there speeds drop. Disabling it keeps the speed up and near 900Mbps. I have this modem however I'm using a CM1100 at the moment as I'm doing other fun stuff.
I am currently using the cm1200 with factory settings and I am getting 930 down and 50 up with xfinity service.
- Excellent. That makes me feel much better. I'll try disabling Aggregated ports tonight and see if that helps.
Let us know how it goes...
Weird. Still no dice. I did a speedtest on boot up with my Xfinity supplied cable modem:
Ping - 14ms
Download - 926.24
Upload - 40.01
Then I hooked up my Netgear cm1200 and factory reset it to insure all settings were default and performed another speed test.
Ping - 15ms
Download - 606.29
Upload - 29.45
Do I just have a faulty one?
Yes. You might try another CM modem...
Thanks for all the advice guys, greatly appreciate the responses. Here's where I stand as of this morning.
- I contacted Netgear support last night and worked with a tech on the call to check all of my cm1200 settings (after a reset to factory). The tech noticed that the power levels for the upload and download channels looked off and stated that Xfinity needed to reprovision the device and that I would need to contact them directly.
- I contacted Xfinity this morning and they reprovisioned the device but I was still seeing only 600 Mbps download. After troubleshooting with the Xfinity tech more he stated that an Xfinity tech would need to come to my house to complete my upgrade to a 1 Gbps plan and scheduled a time for this upcoming Friday. To me, this makes no sense seeing as I can swap out my Netgear modem with my old Xfinity modem and get 950 Mbps. No matter how much I explained this though he was saying I still have to have a tech out. So now I wait for Friday. I'll update back here after that visit to get closer for anyone who might track this thread in the future.
Well what may work for other modems may not work for others. Let the tech come out and check it all. Have the CM1200 online with a wired PC connected directly to the CM modem. Have only Ooklas installable speed test app on your PC running. Disable or exit from all other applications while hes there and heling you test. Take notes and if even after the tech has made any adjustments and can't get the CM modem to speed out at near 900Mbps, then get this information to your NG support case and see about getting an RMA.
kioteh wrote:Thanks for all the advice guys, greatly appreciate the responses. Here's where I stand as of this morning.
- I contacted Netgear support last night and worked with a tech on the call to check all of my cm1200 settings (after a reset to factory). The tech noticed that the power levels for the upload and download channels looked off and stated that Xfinity needed to reprovision the device and that I would need to contact them directly.
- I contacted Xfinity this morning and they reprovisioned the device but I was still seeing only 600 Mbps download. After troubleshooting with the Xfinity tech more he stated that an Xfinity tech would need to come to my house to complete my upgrade to a 1 Gbps plan and scheduled a time for this upcoming Friday. To me, this makes no sense seeing as I can swap out my Netgear modem with my old Xfinity modem and get 950 Mbps. No matter how much I explained this though he was saying I still have to have a tech out. So now I wait for Friday. I'll update back here after that visit to get closer for anyone who might track this thread in the future.
- Can you share with me all your CM1200 settings, so I can match mine?
Only setting that you can configure is LAG and that should be disabled.
- I was reading through this thread and my issue is different. I’m currently experiencing slow wifi speeds, I use to rent xfinity modem and I was averaging 400-450Mbps solid, switched over to cm1200 June 29,2020 averaged 400-450mbps after the first month I noticed my speeds at most 200-250Mbps and now it has dropped to 100-150mbps and under 20mbps at times. I’ve spoken to several Xfinity reps they say my signal is good and they also have reset the signal sent to my cm1200. I have not changed anything since I have set up my cm1200. My set up is cm1200+r8000 router.
Be sure to test with wired connections thru the router and modem.
Wifi speeds results may not be accurate due to many factors that contribute to innaccurate results.
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.
lazybone wrote:
I was reading through this thread and my issue is different. I’m currently experiencing slow wifi speeds, I use to rent xfinity modem and I was averaging 400-450Mbps solid, switched over to cm1200 June 29,2020 averaged 400-450mbps after the first month I noticed my speeds at most 200-250Mbps and now it has dropped to 100-150mbps and under 20mbps at times. I’ve spoken to several Xfinity reps they say my signal is good and they also have reset the signal sent to my cm1200. I have not changed anything since I have set up my cm1200. My set up is cm1200+r8000 router.They did the same with me and replaced the line to the house, no difference. It's the modem or something in the modem settings that does not allow it to get the higher speed that Netgear advertises. Unfortunately my free support period is expired and the Netgear wanted me to pay about $150 to troubleshoot this for me. So I decided to just pay that money and buy a new Xfinity modem directly from them.