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CM1150V and Comcast - can't get gigabit speeds?

kingtj
Star

CM1150V and Comcast - can't get gigabit speeds?

I just upgaded my Comcast Xfinity "Blast" Internet speeds to Gigabit, which required I upgrde my DOCSIS 3.0 Motorola cable modem.  I ordered Comcast voice service too, with this upgrade, so apparently, I had to buy the new Netgear CM1150V cable modem with VoIP support if I didn't want to pay monthly rental for the Comcast solution.

 

Unfortunately?  When I use the Comcast gateway they rented me, I get 940mbbit/sec download speeds and 40mbit/sec up reliably.  When I use the Netgear, I get only 500Mbit/sec download (although still see about 40mbit/sec up).

 

The Comcast tech came out this afternoon and checked the signal levels on the line, and said mine are "excellent" and that's definitely not my problem.  They verified they pushed the correct modem profile to the Netgear too, and insist it's all correct.

 

The tech says he suspects the Netgear modem needs newer firmware to reolve some kind of compatibiliy issue that's slowing it down, but I can't see any way to get newer firmware for it?  He says Netgear has always been troublesome in this regard, since they outsource their modem firmware development and typically don't make updates available for anyone.

 

I really don't want to pay $13/month to keep renting the Comcast router, especially when it has built in wi-fi that can't be turned off, and I have my own solution for wi-fi.  But not sure what to do now?  This prodiuct says it's XFinity multi-gig speed compatible, all over the front of its box, and it's on the Comcast compatibility list.  Yet Comcast has nothing more to suggest.  Could this actually be a defective modem, even though it's reliably running for me at the slower speed and shows all 32 channels are "locked" with good signal to noise ratios and very few errors??

 

Model: CM1000|DOCSIS® 3.1
Message 1 of 23
vkdelta
NETGEAR Expert

Re: CM1150V and Comcast - can't get gigabit speeds?

Pls PM CM MAC/account #/Location/ and  CM Power Levels and event logs.

 

Message 2 of 23
TedInCall
Tutor

Re: CM1150V and Comcast - can't get gigabit speeds?

I have the same issue with the CM1150V modem even when directly connected - So do many others here.

 

Problem with the firmware is that Comcast/Xfinity has to push it to the modem, you can't even though you own it.

 

I guess I'll be returning mine,

Message 3 of 23
kingtj
Star

Re: CM1150V and Comcast - can't get gigabit speeds?

Yeah.... I tried to follow every message thread on here I could find about this CM1150V and speed issues.  And honestly, at least half of the threads did sound like people were having problems with other things like line errors due to poor signal levels on some channels.  That, plus how few people seem to even own this new modem or want to use it on a gigabit speed tier with Comcast, makes it difficult to figure out what's really going on.

 

But I waved the white flag for now.  I surrender.  This modem is getting returned this afternoon and I fought with Comcast for another 2 hours on the phone to get them to re-provision the XB6 router they provided me initially.  (After they got it working for data, it was a big struggle to get the voice provisioning department to do their side of it. Ugh....)   It would be really nice if they'd leave BOTH modem profiles in their system so I could switch back and forth between the two for easier troubleshooting, but they won't.

 

At this point, I'm just hoping a version of this XB6 winds up a product end users can purchase.

Message 4 of 23
Windchaser
Tutor

Re: CM1150V and Comcast - can't get gigabit speeds?

Hi, I am new to Netgear community.   I have a similar issue with Comcast and CM1150V, however it also involves the Orbi RBR50 mesh wifi units.

 

Six months ago I upgraded my network with the Orbi RBR50 and it was attached to the Comcast modem.  We have Comcast "Blast" service and we were getting 150-170 mbps download and 12-15 mbps upload.  All was good in OZ.  

 

Last week I upgraded to the CM1150V to get rid of the monthly modem fee.  When my iMac is connected directly to the CM1150V I get 150-170 mbps down and 10-20 mbps up....HOWEVER, when I connect the CM1150V directly to the Orbi RBR50, the speeds drops to 50-70 mbps down and 11-12 mbps up. This speed is consistant when testing the other satellite units within the house too.  The phone service is working OK.   

 

I purchased the Netgrear units to avoid compatibity issues and simplify the installation.  I went for the CM1150V to be "future proof" with the trend to DOCSIS3.1

 

Now I wondering if the newer DOCSIS 3.1within the CM1150V is not compatible with the DOCSIS 3.0 in the RBR50?

 

I greatly appreciate any insights on how to resolve this issue.

 

Message 5 of 23
Windchaser
Tutor

Re: CM1150V and Comcast - can't get gigabit speeds?

UPDATE

I completely rebooted the CM1150V, Orbi and the satelites and the network is now back to 180 mbps.  I see where I went wrong, I just turned off/on the Orbi when I installed the CM1150V and did not go through the process of restaring everything from scratch.  

Message 6 of 23
jrowlands
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

I have the Netgear CM1150v Docsis 3.1 cable modem telephony and am curious about the downstream channels. Channel 32 is not locked on. Channels 1-31 are locked on, but I do not see any of the Docsis 3.1 frequencies allocated to the modem. I was told the Docsis 3.1 frequencies are above 677Mhz. My frequencies are 477-677. I am experiencing erratic download speeds while the upload speeds are somewhat consistent ranging between 32-41mbps. Downloads range from 647mbps down to 25mbps. Powering the modem, re-provision from xfinity, multiple technician visits, and so on. Any help?

Message 7 of 23
MichaelMs
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

I had the same experience. Resigned with Comcast for triple play option and needing a modem with voice. Before I had only Comcast internet using my own Motorola modem (docsis 3.0 with four network ports). With this modem only one WAN port routing/forwarding to the four internal ports. Speed was ~150 mbps. I was disappointed when switching to CM1150V. Could not connect 4 different devices to the 4 ports. Was missing the routing option in the config under 192.168.100.1. Speed dropped to <90mbps and I did not like the Comcast dependency regarding the firmware. I would have not been interested to maybe pay for 4 WAN addresses. I switched back to my old modem with separate modem for voice and will monitor the docsis 3.1 for a little.
Message 8 of 23
plasmic44
Tutor

Re: CM1150V and Comcast - can't get gigabit speeds?

I'm having the same issue with the CM1150V, which has no line errors or power issues, and every channel is locked on. A Comcast tech was here yesterday to test the line, and when plugging the coax directly into his equipment, he was receiving download speeds of 1.1Gpbs (he showed me). But when plugged into the modem, I'm getting no more than ~260Mbps. 

 

Oddly, when I run an Internet speedtest within my router (Nighthawk X4S, there's an option to run a speedtest directly from the console), it shows speeds of 650Mbps. But that's not the case when I run a speedtest through a browser.

Message 9 of 23
antinode
Guru

Re: CM1150V and Comcast - can't get gigabit speeds?

> [...] my own Motorola modem (docsis 3.0 with four network ports [...]

 

   Not a very detailed description of anything. "four network ports"
suggests that this "modem" is actually a modem+router.

 

> [...] I was disappointed when switching to CM1150V. Could not connect
> 4 different devices to the 4 ports. Was missing the routing option [...]

 

   Replacing a modem+router with a simple modem might be expected to
cause the loss of router functionality.

 

> [...] I did not like the Comcast dependency regarding the firmware.
> [...]

 

   If you can get firmware for any DOCSIS device without going through
your ISP, then many people around here would like to learn how.

Message 10 of 23
plasmic44
Tutor

Re: CM1150V and Comcast - can't get gigabit speeds?


@plasmic44 wrote:

I'm having the same issue with the CM1150V


I managed to isolate two issues that were majorly degrading my performance, and neither were related to the CM1150V. First, I was connected to my PC's gigabit adapter, but it was a PCI adapter. PCI bandwidth tops out at 266Mbps. I upgraded to a PCIe gigabit adapter ($10 on Amazon), and my speeds were better, but still not approaching gigabit.

 

The second issue was my antivirus. Avast runs four "Core Shields," so I turned each off one at a time and retested speeds. The culprit was the Web Shield. I turned that off, and now I'm getting 800+Mbps during peak periods. I'll try it again during non-peak and see if it's even closer to gigabit.

Message 11 of 23
marindavid
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

No Gigabite speed here!

Xfinity teach redid all the wiring and fitting - modem as reset twice - stll in the 200s. Seems to need new firmware. Shall I return it like it sounds like so many other have done?

Is anyone at Netgear paying attention to what is happening here?

Message 12 of 23
FURRYe38
Guru

Re: CM1150V and Comcast - can't get gigabit speeds?

How are you testing speeds? Wired PC will be needed. Use Ooklas speed test app installed in Windows or Mac. 

What is the specs of the wired PC. 


@marindavid wrote:

No Gigabite speed here!

Xfinity teach redid all the wiring and fitting - modem as reset twice - stll in the 200s. Seems to need new firmware. Shall I return it like it sounds like so many other have done?

Is anyone at Netgear paying attention to what is happening here?


 

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router RBK953 (Router Mode) 2.5Gb Wired Backhaul | Switches NG GS105/8, GS308v3, GS110MX and XS505M | XR1000 (Router Mode) and RBK853 AP Mode  | 

Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, R7000, R7800, R7960P, R8000, R8500, RAXE500, RAX50, XR450, EX7500/EX7700

Message 13 of 23
dnegg
Initiate

Re: CM1150V and Comcast - can't get gigabit speeds?

The  Netgear CM115V Modem is not worth the hype! Had to call Comcast 3 times to get it activated, poor speed with a Netgear router. Returning it for an Arris.

Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 14 of 23
love2scuba
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

I had gigabite speed when I first installed the CM1150V modem. When I hooked up my AC1750 router the speed almost went to zero if I use the port on the modem.  If I move it over to the router it is in the mid 500's along with the wireless speeds.  Current firmware on the router: 
V1.0.3.66_10.0.50

 

Any thoughts??

Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 15 of 23
FURRYe38
Guru

Re: CM1150V and Comcast - can't get gigabit speeds?

I would post about this in the router appropriate forum.

If your getting speeds with out the router at the cable modem, then the router needs to be look at. 


@love2scuba wrote:

I had gigabite speed when I first installed the CM1150V modem. When I hooked up my AC1750 router the speed almost went to zero if I use the port on the modem.  If I move it over to the router it is in the mid 500's along with the wireless speeds.  Current firmware on the router: 
V1.0.3.66_10.0.50

 

Any thoughts??


 

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router RBK953 (Router Mode) 2.5Gb Wired Backhaul | Switches NG GS105/8, GS308v3, GS110MX and XS505M | XR1000 (Router Mode) and RBK853 AP Mode  | 

Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, R7000, R7800, R7960P, R8000, R8500, RAXE500, RAX50, XR450, EX7500/EX7700

Message 16 of 23
Orgramos
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

I am having similar but worst issue. Despite it is one of the comcast compatible modems. Neither comcast not netgear technician were able to fix the issue. No or intermittent connectivity. So i am returning modem, router, and canceling my comcast. Going with ATT.
Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 17 of 23
FURRYe38
Guru

Re: CM1150V and Comcast - can't get gigabit speeds?

May have been a bad modem. 

Cabling should have been checked.

 

Good Luck. 


@Orgramos wrote:
I am having similar but worst issue. Despite it is one of the comcast compatible modems. Neither comcast not netgear technician were able to fix the issue. No or intermittent connectivity. So i am returning modem, router, and canceling my comcast. Going with ATT.

 

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router RBK953 (Router Mode) 2.5Gb Wired Backhaul | Switches NG GS105/8, GS308v3, GS110MX and XS505M | XR1000 (Router Mode) and RBK853 AP Mode  | 

Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, R7000, R7800, R7960P, R8000, R8500, RAXE500, RAX50, XR450, EX7500/EX7700

Message 18 of 23
CoolioBeans
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

After some INTENSE expiditions through the internet I fell upon this reddit post:

https://www.reddit.com/r/HomeNetworking/comments/6eunbs/xfinity_250_mbps_plan_only_getting_8090_mbps...

A guy reccomends pushing in the the ethernet cable gauranteeing a perfect fit, because anything above 100Mbps needs all 4 ethernet contacts connected if it detects any less it will default to less than 100Mbps. I thought this was crap so I tried and it worked!!! getting 200+Mbps on my 175Mbps plan. Man Surprised

 

PLEASE SHARE THIS ON ALL OF THE FORUMS YOU'VE CHECKED ALREADY!! I WILL DO THE SAME!

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 19 of 23
antinode
Guru

Re: CM1150V and Comcast - can't get gigabit speeds?

> [...] pushing in the the ethernet cable gauranteeing a perfect fit,
> [...]

 

   If the cables/connectors are good, then you shouldn't need to do
anything special to get a proper connection.  "Click" should be all you
need.

 

> [...] anything above 100Mbps needs all 4 ethernet contacts connected
> [...]

 

   Anything above 100Mb/s needs all _eight_ conductors.

 

   In any case, this is why Ethernet connectors frequently have
associated LED indicators.  Visit http://netgear.com/support , put in
your model number, and look for Documentation.  Get the User Manual.
Look for the LED descriptions.  For example, in the CM1150V User Manusl
(page 8):


        o Green.  A powered-on device is connected to the Ethernet port
          at 1000 Mbps.

 

        o Amber.  A powered-on device is connected to the Ethernet port
          at 10 Mbps or 100 Mbps.

 

   None of this information is very well hidden.

Message 20 of 23
VPNTrouble
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

I had the same problem. I had the warrenty so I returned it and they gave me a new one. I had the same problem with it. In the beginning I had the correct speed. After several comcast techs ,new cables I took my modem back for a refund and went with the rental. Did this fix your issue.
Message 21 of 23
marindavid
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

With me, the problem turned out to be with Comcast/Xfinity. It took them 5-months to get my area up to GB speed and, in that time, they credited my monthly bill with an amount equal to what the speed upgrade had cost me. Now, my desktop, which is hard-wired to the Netgear Modem, measures at 375-600 Mbps. When it falls below that, I reboot the modem and, quickly, all is well again. The problem is not always our hardware or US!

Message 22 of 23
VPNTrouble
Aspirant

Re: CM1150V and Comcast - can't get gigabit speeds?

I think the problem was comcast made some type of boot file that made the netgear not capable to handle the gig speed. Maybe all it would have took was raising a limit in the netgear set up but comcast was not going to tell us. I battled for several weeks and as soon as I installed there doc 3.0 gateway I went from 400 to 900 plus. The modem I was using was doc 3.1. Sucks. You know comcast could have told me how to fix it but they would not cause it was my equipment.
Message 23 of 23
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