CM1000v2 modem with slow speeds of 256mbps

[lbruski43]

I have a Netgear CM1000v2 modem and a r8000p router and 1.2 gig service. Speedtest download speed only around 256 mbps. Both modem and router capable of gig speeds but not getting it on speed test . Help !

[FURRYe38 · Accepted solution]

Any Criticals, Errors or Warnings seen in the NG modems event logs needs to be reviewed by the ISP and resolve by the ISP. These indicate a signal line issue from the ISP.

[FURRYe38]

Are you seeing near 900Mpbs with a ethernet connected PC to the CM modem with out the router in the middle? 

Be sure to use Ooklas installable speed test app for Windows and Apple

[lbruski43]

Thank you Furrye38 for your quick response. I read where I could test this way but have not done yet. I will do this as soon as other users are off line and respond back. Should complete in a couple hours. Would appreciate you checking back in after my response.
Thanks again !!

[FURRYe38]

When you can please post the following:

Please post a copy and paste of the modems connection status and event log page.
https://kb.netgear.com/30007/How-do-I-obtain-the-cable-connection-information-from-a-NETGEAR-cable-m...
https://kb.netgear.com/30008/How-do-I-view-or-clear-the-event-logs-on-my-NETGEAR-cable-modem-or-mode...

Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended. 

[lbruski43]

Posted results from status you requested. Yes , when I bypass router I am getting 900 plus mbps so it appears I am getting my gig speeds from Xfinity. I then reconnected to router and tested different angles on my router antennas but best top speed was around 650 mbps. These tests were done sitting in front of modem and router. I then went to my living room where I use my iPhone and iPad . That is where I am only acheiving the average 250 or so mbps. I know walls and such cause distortion , but my Netgear modem and router make dels tout big whole house coverage . My home is only 2100 sq. Ft. I know moving the location of router/modem to my living room would help , but while sitting in front of them in current location , I could only achieve the 650 or so average , big drop off from the gig. Do you see anything abnormal or have any suggestions ?
Thanks !

[lbruski43]

Does anyone have any suggestions ? Furrye38 ?

[FURRYe38]

Don't see the information requested. 

Has a factory reset and setup from scratch been performed since last FW update? A complete pull of the power adapters for a period of time after the factory reset then walk thru the setup wizard and setup from scratch with a wired PC and web browser. Recommend setting the default DHCP IP address pool range to the following after applying and a factory reset: 192.168.#.100 to 192.168.#.200.
https://kb.netgear.com/24089/How-do-I-specify-the-pool-of-IP-addresses-assigned-by-my-Nighthawk-rout...

[lbruski43]

FURRYe38 below is the first posting you requested.


Time Priority Description
2023-06-17, 03:21:06 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 03:21:06 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 03:20:53 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2023-06-17, 03:20:47 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:35 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:34 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:34 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:33 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:32 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:28 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:28 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:12 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-17, 01:23:10 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:30:50 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:30:32 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:15:54 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:15:53 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:15:53 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:15:53 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:15:47 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-13, 15:15:27 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-03, 21:36:27 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-03, 21:36:08 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-03, 12:36:44 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-03, 12:36:25 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-03, 12:35:45 Critical (3) Resetting the cable modem due to docsDevResetNow
2023-06-01, 19:29:15 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-01, 19:29:01 Critical (3) UCD invalid or channel unusable;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-01, 19:28:24 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-01, 19:27:49 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-01, 19:29:05 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-06-01, 19:24:48 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2023-05-17, 13:50:22 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:4a:58;CMTS-MAC=00:90:f0:09:01:00;CM-QOS=1.1;CM-VER=3.1;

[lbruski43]

No , I have not completed a reset of modem . My modem and router were just plugged in and used with existing setups. No adjustments or resets done , as I am a novice at doing anything but plug and play. I fear doing the adjustments in fear of causing more problems.

[FURRYe38 · Accepted solution]

Any Criticals, Errors or Warnings seen in the NG modems event logs needs to be reviewed by the ISP and resolve by the ISP. These indicate a signal line issue from the ISP.

[Kitsap]

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@lbruski43 wrote:
Posted results from status you requested. Yes , when I bypass router I am getting 900 plus mbps so it appears I am getting my gig speeds from Xfinity. I then reconnected to router and tested different angles on my router antennas but best top speed was around 650 mbps. These tests were done sitting in front of modem and router. I then went to my living room where I use my iPhone and iPad . That is where I am only acheiving the average 250 or so mbps. I know walls and such cause distortion , but my Netgear modem and router make dels tout big whole house coverage . My home is only 2100 sq. Ft. I know moving the location of router/modem to my living room would help , but while sitting in front of them in current location , I could only achieve the 650 or so average , big drop off from the gig. Do you see anything abnormal or have any suggestions ?
Thanks !

---

Based on the areas in bold, I conclude you are testing over Wi-Fi.  If that is the case, you will not see Gbps throughput.  In fact, the 650 Mbps is outstanding.  For consistent results, make sure you are using the Ookla installable test application.  It is available in your play store.  Avoid web browsers and web sites for throughput testing.

For some background reading on Wi-Fi speeds, this is a great reference:

https://www.duckware.com/tech/wifi-in-the-us.html

Duckware is solid in their technical details.

[lbruski43]

Thank you Kitsap , I downloaded the Duckware article and bookmarked . I found it very helpful in understanding my question’s answer.