CM1150V - LAN speed drops from 1000 to 100 MBPS - Thermal Throttle past 75C

[Monkmad]

All,

I'm posting this for two reasons:

- So someone else in the same situation can (hopefully) find this thread and figure out what is going on

- To request Netgear to update their settings due to climate change 😉 

I've spent the past few weeks frustrated and running around in circles, as my 400+MBPS ISP connection would connect (on the LAN side) at 1GBPS, but drop in a few minutes to 100MBPS. The ISP (Comcast) reprovisioned the modem multiple times and ran tests on their end to no avail. I changed the ethernet cable between modem and wifi router, even changed the router itself, but the problem wouldn't go away.

I'll save you my long story of misery, but last night, I finally found the root cause while going through the Event Log of the CM1150V (Adavnced --> Administration --> Event Log).

Here is what it said:

Critical (3) THERMAL THROTTLE: Temperature 75C, transition to state Elevated 1

Now, I don't know about y'all, but where I live (Texas), we've had some high temperature days this season (>100 F/38 C).

I tested by placing two giant fans near the cable modem and blasting away. Here is what it said after a few minutes:

Critical (3) THERMAL THROTTLE: Temperature 73C, transition to state Normal

I've retested it, and these events perfectly correspond to the ETHERNET link dropping from 1 GBPS to 100MBPS (or vice-versa). The Ethernet port light also switches from Green to Amber, and the other way around. (This was the clue which led me to this discovery eventually).

So, here is my request to Netgear:

- Is there a way to add a heat sink or some other solution to the modem for indoor applications in hot climates like the Southern US?.

- Can you please update the throttle setting to a higher temperature in the next FW update, or make it configurable? At the very least, give the customer a way to disable the throttle (show them all the legal disclaimers, and void their warranty if needed).

Thanks,

Frozen in Texas with my AC set to 76 F / 25 C

[FURRYe38]

@vkdelta 

[vkdelta]

@Monkmad

  Please PM me.

[bobalay]

I just activated this modem yesterday and already set up an RMA for it, way too many issues. Everytime I connect a device to it I have to powercycle it in order for the device to connect. And even when I do that one device might connect but another will lose connectivity and vice versa. I must of rebooted that modem 1000x over the past 24hrs between me working on it and w/ xifinty tech support. Another thing is I got a 928mbps down / 38mbps up speed test on my cheap laptop but on my main gaming rig I can't get anything higher than 98mbps up but I do get 40+mbps up. All connected via CAT6. I had no problem getting 300+mbps w/ my docsis3.0 modem but w/ the docsis3.1 my rig won't break 100mbps. Also I can't connect more than one device to the ethernet ports, port1 goes green but the other remain amber. Anyone else having issues w/ theirs? 

[vkdelta]

@bobalay 

Please provide event logs and DOCSIS power table for review

Device-A gets 928/38 but device-B gets 98/40. Is the ethernet link at gig or 100Meg? Please have screenshot of both the CPEs ethernet connection.

you CANNOT connect other ports UNLESS you have MULTIPLE-IP service from your ISP

OR you are using LAG/LACP.

It looks like you dont have either one of them, so you setup will be limited to 1 ethernet port.

[bobalay]

I can't send the logs, I already packaged the modem to return. I did however, activate my new modem just a little while ago and this time it went much smoother. I only connected to the other ports because I was messing to see if my router would do line aggregation. The issue is my netgear router. I tested the speed of this modem directly connected and got 930/38 w/ both my laptop and my gaming pc. That's not the case when connected via the router, I'm only getting 95/38. I did a factory reset on the router and still, the speeds remain the same. QOS is not enabled. Oh by the way the wifi speeds are fine at around 550/39.

My setup info...

Comcast 1000/35 speed tier

Netgear CM1150V modem

Netgear Nighthawk X6 R8000 router

Firmware: V1.0.4.28_10.1.54

PC Specs:

Intel(R) Core(TM) i7-7700K CPU

ASUSTeK MAXIMUS IX HERO Motherboard

BIOS Version/Date American Megatrends Inc. 1301, 3/14/2018

Installed Physical Memory (RAM) 32.0 GB

NVIDIA GeForce GTX 1080

Everthing is wired via CAT6 and my ethernet speed/duplex is set to auto negotiate. If I manually set it to 1Gbps full, I lose connection & it says there's no network connection.

[FURRYe38]

The R8000 doesn't support LAG. The R7960P does and I think the R8000P does. 

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@bobalay wrote:

I can't send the logs, I already packaged the modem to return. I did however, activate my new modem just a little while ago and this time it went much smoother. I only connected to the other ports because I was messing to see if my router would do line aggregation. The issue is my netgear router. I tested the speed of this modem directly connected and got 930/38 w/ both my laptop and my gaming pc. That's not the case when connected via the router, I'm only getting 95/38. I did a factory reset on the router and still, the speeds remain the same. QOS is not enabled. Oh by the way the wifi speeds are fine at around 550/39.

My setup info...

Comcast 1000/35 speed tier

Netgear CM1150V modem

Netgear Nighthawk X6 R8000 router

Firmware: V1.0.4.28_10.1.54

PC Specs:

Intel(R) Core(TM) i7-7700K CPU

ASUSTeK MAXIMUS IX HERO Motherboard

BIOS Version/Date American Megatrends Inc. 1301, 3/14/2018

Installed Physical Memory (RAM) 32.0 GB

NVIDIA GeForce GTX 1080

Everthing is wired via CAT6 and my ethernet speed/duplex is set to auto negotiate. If I manually set it to 1Gbps full, I lose connection & it says there's no network connection.

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