Community Forum

Unfixable? Slow Speeds

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Frequent Visitor

Unfixable? Slow Speeds

I have a problem that seems to be a common one. I pay for the 200mbps download speeds. I can only ever achieve roughly 90mbps on average. Often slower in the 70-80 range. This is for any device. This has been like this since I had changed service to add Television to my package years ago. I have been with Comcast forever, literally. I first brought cable Internet in when the service was owned by @home. No throttle on this servive. Along the years, @home was sold off and eventually arrived with Comcast. During some initial troubleshooting that has to go back 10 years, one technician commented that he was amazed that I had no filter or clamp on my speeds. Many years later after adding TV, my entire neighborhood hit the limit where nothing but pixelization was present on any TV signals. After a month of conversations with Comcast, they sent out a crew of 8 or more trucks and line crews and ran new runs from the end of the node back. TV became better, but I now had a throttle and speeds dropped down to 90mbps at that point.

 

Fast forward this 10 years now. I have entirely upgraded my internal network. I run a Netgear CM600 with DOCSIS 3.0 and 960MBPS max. speeds. No improvement. I upgraded to the latest Linksys AC1900 router along with a 2nd ASUS RT-AC3200. All gigbit equipment. I even replaced my switch. I had an old Linksys gigbit switch that I upgraded along the way with hopes of improvement. My wired or wireless speeds are the same. Of note, when going modem direct to my laptop with a gigbit card, the speeds remian at the 90mbps range. Within teh last month, I had a tech out for poor TV reception. He rewired everything and replaced the splitter to a monster block about 10" square. Every connection was re-run and new runs made in some cases. He was complete as possible with checking levels at every interface. When we got to the download speeds, he again checked everything on my end and could not resolve any improvement or make any improvements.

 

Going modem direct certainly implied not on my end. Interestingly enough, my neighbor next dooe gets 150mbps down on a slower package and the absolute last home on our node. I have even ran a new cable directly from the outside box through my window directly to the modem without impacting any change. That connected nothing else other than the modem. Every device in my home reports the same speed results either wired or wireless. The tech that came out suggested there may be a very old clamp or filter somehwere in the line likley at the pole or elsewhere only on my drop. Or possibly, there is some disconnect on Comcast's side that never removed or changed the throttle for my speeds after upgrading to the 200mbps package. So my result is literally years of this frustration of my family complaining about inability to stream without buffering, slow internet on their phone or tablet etc.

 

The bottom line is that I have upgraded and am paying much more for this package and I am not getting what I am paying for. I am about at the point where I have no faith that Comcast can resolve this. Over the years probably 10 different techs have tried and now I think dumping Comcast may be my only option as nobody seems willing to take on the challenge to fix what seems to be unfixable A change in provider may be my only solution. This forum post is now my last attempt to try and fix this.

 

BTW, all modem signals ar rock solid (Power, SNR etc.. All within ranges. Almost nominal to the letter). I have read hundreds of articles, reset modems and router hundreds of times, reset back to facotry defaults, changed Wifi channals and just about everything else anyone suggests. The bottom line is modem direct is same as full network connected and even fresh cable run.

 

One last note, I tried replacing all of my network cables from cat 5 to cat 7. Of course no improvement there either. Also on my Netgear CM600, I started with the Comcast modem and was at 90mbps and this purchase was an attempt to improve the speeds. I have probably $3000 invested in the best routers, solid modems, cables, upgrades peed packages etc.  So who out there is going to be my hero and find my problem?? I will try anything at this point. I hate to have to switch providers

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Frequent Visitor

Re: Unfixable? Slow Speeds

No help? Nobody has any ideas?

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Frequent Visitor

Re: Unfixable? Slow Speeds

Make sure there is not a setting in the router slowing the speed. Turn qos off to make sure.
If using window 10, download the ookla speed app from the Microsoft app store and test speed with it. It takes any browser interference out of the equations.
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Frequent Visitor

Re: Unfixable? Slow Speeds

Thanx for the response. Qos is off. Xfinity speed test shows equal to Ookla within a few %. I typically opt for Ookla and have the app installed on all devices. I just upgraded to Windows 10 Pro, but speeds are the same on 7 Pro and even an old programming laptop I use that still uses XP. I have tried different frequencies on the modem with notable change in levels of power or SNR. Certainly no speed changes. Routers are out of the equation as modem direct to PC results in identical speed results. Thanx again for the suggestions
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Frequent Visitor

Re: Unfixable? Slow Speeds

What does anybody knopw about traps or filters on teh lines? I went out and checked my box on the house today as this is mind bendingly frustrating to pay for something you are not getting. Within teh box are all good solid connections. This was redone during my last tech visit but no speed improvement has been made. So here I sit paaying for 200mbps and get 85'ish. I have run across some youtube and other websites that discuss very old drops that have traps or filters on them that have been removed and have corrected problems. Does anyone have any insight as to the potential of this being a contribitor to slow speedss. I want to again make teh statement that modem direct into a gigbit Nic is the same as with all routers connected.

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Diamond Problem Solver

Re: Unfixable? Slow Speeds

If there was trap/filter anywhere it would be reflected in the downstream/upstream channels of your modem.

I am a Retired Official Comcast Employee
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Frequent Visitor

Re: Unfixable? Slow Speeds

Can you elaborate. Speeds are exactly the issue. Short of grabbing a ladder and following the cable line back, does this seem to be a potential cause? Although the neighborhood was overhauled, the drop to my house is the same one from probably 30+ years ago. Probably more. I was the engineer for Centel Phone company who had to create pole assignments and phone line drops to make room for the cable lines to fit
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Diamond Problem Solver

Re: Unfixable? Slow Speeds

Post your modem’s downstream and upstream signal levels. A filter or trap if present could be A cause but doesn’t mean it’s THE cause. If you think your drop is that old have a tech out to replace it. I don’t recall if you’ve tried a Comcast gateway instead of your own equipment. Techs have a piece equipment that tells exactly what speeds your modem gets, has that ever been done? Your previous employer doesn’t play a factor.

I am a Retired Official Comcast Employee
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark a post as the Best Answer!
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Frequent Visitor

Re: Unfixable? Slow Speeds

The previous employer was for timeline. More than 30 years ago I will post levels tomorrow. There very nominal and within prescribed ranges per latest tech visit. Everyone that comes out from Comcast wastes hours and nets zero gain. If I suggest the trap or filter, I get condescending rebuttals and zero action. They all blame the last tech on his poor work, redo all connections. After hours, no change. Some promise they will elevate it come back with another modem to swap as a test. Nothing but radio silence. The single time I have received satisfaction was after directly contacting the VP of customer satisfaction. That was the result of new lines run throughout the neighborhood. Coincidentally when my speeds tanked.
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Regular Contributor

Re: Unfixable? Slow Speeds

By any chance are your computers a Dell? If so, there was a post where a fella got slow speeds, he found out Dell loads a program that throttles downloads, he removed the program and all was good.

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Frequent Visitor

Re: Unfixable? Slow Speeds

One computer is a dell. The others are MacBook Pro laptops. Same speeds across all phones, tablets and devices. Direct modem in is the same speed as all routers connected
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Frequent Visitor

Re: Unfixable? Slow Speeds

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency
 
Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 573000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only
 
<tabindex=-1>Downstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 13 573000000 Hz -1.5 dBmV 40.0 dB 1936 603
2 Locked QAM256 14 579000000 Hz -1.5 dBmV 39.9 dB 1924 398
3 Locked QAM256 15 585000000 Hz -1.6 dBmV 39.9 dB 1931 253
4 Locked QAM256 16 591000000 Hz -1.8 dBmV 39.8 dB 1800 473
5 Locked QAM256 17 597000000 Hz -1.9 dBmV 39.7 dB 1884 725
6 Locked QAM256 18 603000000 Hz -1.8 dBmV 39.8 dB 1826 344
7 Locked QAM256 19 609000000 Hz -1.8 dBmV 39.8 dB 1722 499
8 Locked QAM256 20 615000000 Hz -2.1 dBmV 39.7 dB 1706 555
9 Locked QAM256 21 621000000 Hz -2.1 dBmV 39.6 dB 1720 408
10 Locked QAM256 22 627000000 Hz -2.5 dBmV 39.4 dB 1724 428
11 Locked QAM256 23 633000000 Hz -2.3 dBmV 39.6 dB 1689 309
12 Locked QAM256 24 639000000 Hz -2.3 dBmV 39.5 dB 1834 375
13 Locked QAM256 25 645000000 Hz -1.8 dBmV 39.8 dB 1652 279
14 Locked QAM256 26 651000000 Hz -2.0 dBmV 39.6 dB 1659 319
15 Locked QAM256 27 657000000 Hz -2.2 dBmV 39.5 dB 1766 494
16 Locked QAM256 28 663000000 Hz -2.2 dBmV 39.5 dB 1708 301
17 Locked QAM256 29 669000000 Hz -1.9 dBmV 38.1 dB 0 0
18 Locked QAM256 30 675000000 Hz -2.1 dBmV 37.7 dB 0 0
19 Locked QAM256 31 681000000 Hz -2.3 dBmV 37.6 dB 0 0
20 Locked QAM256 32 687000000 Hz -2.4 dBmV 37.6 dB 0 0
21 Locked QAM256 33 693000000 Hz -2.4 dBmV 37.1 dB 0 0
22 Locked QAM256 34 699000000 Hz -2.4 dBmV 37.5 dB 0 0
23 Locked QAM256 35 705000000 Hz -2.4 dBmV 37.3 dB 0 0
24 Locked QAM256 36 711000000 Hz -2.6 dBmV 37.5 dB 0 0
 
<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35800000 Hz 44.8 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29400000 Hz 45.0 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 23000000 Hz 44.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16600000 Hz 45.8 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
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Frequent Visitor

Re: Unfixable? Slow Speeds

2020-02-15, 07:00:26 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:54:10 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:54:10 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:53:42 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:53:42 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:53:14 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:53:14 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:52:35 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:52:35 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:50:02 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-08, 10:49:56 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:56:20 Critical (3) SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:56:09 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:55:38 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:54:32 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:54:30 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:53:44 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:52:00 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:51:09 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:51:05 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:51:04 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 15:50:27 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-02-06, 01:02:56 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-01-22, 01:06:32 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-01-19, 09:58:45 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-01-18, 16:47:10 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-01-18, 16:47:10 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;
2020-01-18, 16:47:10 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=dc:ef:09:8c:5b:e8;CMTS-MAC=00:01:5c:86:20:5b;CM-QOS=1.1;CM-VER=3.0;