brintonh's profile

Contributor

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33 Messages

Sun, Mar 28, 2021 12:56 PM

Help! Can't figure out GB speed issue

Windows 10, LAN on MB (10/100/1000).  MoCA filter and splitter where cable enters house - one leg to video distribution box, second leg directly to my modem.  Had 200 MB plan and was getting around 180 MB.  Upgraded plan to 1200 MB and modem (Arris SB8200, DOCSIS 3.1), Cat 6 directly from desktop directly to modem port just to test - would "spike" speed to around 700 MB then immediately throttle down to 320 MB - 380 MB.  Reset and reprovisioned modem twice.  No change.  Had Comcast Tech out who checked speed at pole (1200 MB), speed at tap for house (1200 MB), speed at modem (1200 MB) with "excellent power levels" per Xfinity Tech.  Add SB8200 in the mix and speed drops to 320-380 MB.  Tech said "Speeds based on our equipment.  SB8200 might not hold full boot file. Try our Xfi modem."  Did that - same speeds.  Would spike to around 600 MB then drop back to 320-380 MB.  Hmmm, ok.  Try another gig speed modem.  Got a Netgear CM1200 yesterday.  Set up with Cat 6 direct from desktop to modem.  Testing wee hours of the AM and get a little better but not much - certainly not 1 GB. 

  Using speedtest.net app in W10 rather than browser test - Browser test is consistently 50-100 MB slower.  Modem reports:

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 627000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 32 627000000 Hz 7.8 dBmV 41.2 dB 0 0
2 Locked QAM256 1 435000000 Hz 6.3 dBmV 40.6 dB 0 0
3 Locked QAM256 2 441000000 Hz 6.1 dBmV 40.5 dB 0 0
4 Locked QAM256 3 447000000 Hz 6.3 dBmV 40.5 dB 0 0
5 Locked QAM256 4 453000000 Hz 5.9 dBmV 40.5 dB 0 0
6 Locked QAM256 5 459000000 Hz 5.8 dBmV 40.5 dB 0 0
7 Locked QAM256 6 465000000 Hz 5.4 dBmV 40.4 dB 0 0
8 Locked QAM256 7 471000000 Hz 5.5 dBmV 40.4 dB 0 0
9 Locked QAM256 8 477000000 Hz 5.5 dBmV 40.4 dB 0 0
10 Locked QAM256 9 483000000 Hz 5.8 dBmV 40.5 dB 0 0
11 Locked QAM256 10 489000000 Hz 6.1 dBmV 40.5 dB 0 0
12 Locked QAM256 11 495000000 Hz 6.4 dBmV 40.4 dB 0 0
13 Locked QAM256 12 507000000 Hz 6.7 dBmV 40.5 dB 0 0
14 Locked QAM256 13 513000000 Hz 6.8 dBmV 40.6 dB 0 0
15 Locked QAM256 14 519000000 Hz 6.3 dBmV 40.6 dB 0 0
16 Locked QAM256 15 525000000 Hz 6.6 dBmV 40.8 dB 0 0
17 Locked QAM256 16 531000000 Hz 6.1 dBmV 40.8 dB 0 0
18 Locked QAM256 18 543000000 Hz 6.1 dBmV 40.7 dB 0 0
19 Locked QAM256 19 549000000 Hz 6.1 dBmV 40.7 dB 0 0
20 Locked QAM256 20 555000000 Hz 6.7 dBmV 40.9 dB 0 0
21 Locked QAM256 21 561000000 Hz 7.1 dBmV 40.9 dB 0 0
22 Locked QAM256 22 567000000 Hz 7.4 dBmV 41.1 dB 0 0
23 Locked QAM256 23 573000000 Hz 7.4 dBmV 40.9 dB 0 0
24 Locked QAM256 24 579000000 Hz 7 dBmV 40.9 dB 0 0
25 Locked QAM256 25 585000000 Hz 6.8 dBmV 40.8 dB 0 0
26 Locked QAM256 26 591000000 Hz 6.5 dBmV 41 dB 0 0
27 Locked QAM256 27 597000000 Hz 6.1 dBmV 41.1 dB 0 0
28 Locked QAM256 28 603000000 Hz 6.9 dBmV 41.2 dB 0 0
29 Locked QAM256 29 609000000 Hz 5.8 dBmV 41 dB 0 0
30 Locked QAM256 30 615000000 Hz 7 dBmV 41 dB 0 0
31 Locked QAM256 31 621000000 Hz 6.7 dBmV 41 dB 0 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35600000 Hz 43.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 44 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 44 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 44 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
 
Downstream OFDM Channels
Channel Lock
Status
Modulation /
Profile ID
Channel
ID
Frequency Power SNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1 Locked 0 ,1 ,2 ,3 33 678000000 Hz 7.7 dBmV 40.6 dB 1108 ~ 2987 107783651 105295721 0
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0
 
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV
 
Extended Upstream Transmit Power
Enable Extended Upstream Transmit Power
 
Current System Time:Sun Mar 28 06:41:00 2021
System Up Time:13:47:03

I'm at a loss to explain why I'm not getting the plan's reported speed.  I think I've isolated just about everything on the system except changing out LAN card in desktop but I'm thinking that's not it since I was briefly seeing 700-800MB before it dropped back down to 320-380MB.  Coax cable from tap on line to modem - check (good - no interference, no power drop, per Xfinity Tech).  Cat 6 - check (good, tried two different ones).  Modem - Check (three different modems, three different manufacturers).  Power levels in spec - check (Xfinity Tech confirmed). 

I'm at a loss to figure this out.  Hopefully someone will have an idea.  

Responses

Official Employee

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314 Messages

6 m ago

Greetings, @BobH2015! I hope your week has been treating you well. Thanks so much for taking a moment out of your busy day to leave a post on our community forum. I'm sorry to hear you're having issues with your connection speeds, but you have definitely come to the right place for assistance. Out of curiosity, what kind of speeds are you getting over WiFi? Is it any better than the LAN speed, or about the same?

scraig2

Contributor

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60 Messages

6 m ago

Same issue here. I have the SB8200 and have tried everything. My guess is the boot file. 

bikeman017

Contributor

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27 Messages

6 m ago

Recently started having slow Speeds on Gigabit,  Contacted Comcast Support on Reddit,  on Wifi Ax on my XB7 Gateway, previously worked fine, average around 737 download and 41 for upload,  yesterday was getting 90-100mb,  link speed was like 113 at one point,  Phone was only at 144mbps for link speed for My Galaxy S20 FE 5G phone,  Now that they somehow got my Gateway on Wifi AC mode, it's holding Link Speed at 866.7mbps, which is better than yesterday

But Heck i pay for Gig Speed, i expect to at least sorta get close to Gig Speed, I know alot of wifi around here,  wiring up this Desktop PC soon as i can get some Flat Ethernet cable, hopefully i get Close to Gig then

If for some reason can't provide Gig speed in this area, i'd least like a Credit for the bill, as it was working just fine up til recently, i don't know what the heck changed,  not my fault if neighbors got a newer router and broadcasting too much on 160mhz or whatever,    just moved into this Complex in November 2019,  worked perfectly fine on Gig from July 2020 on--til now

(edited)

Official Employee

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438 Messages

@bikeman017 Thanks so much for taking the time to reach back out to us regarding your slow speeds over wifi. I know how frustrating slow connection issues can be especially when you feel like you are not getting the speed levels that you are paying for. Have you been able to test that connection over an ethernet to see if there is any kind of improvement with the connection? 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
brintonh

Contributor

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33 Messages

6 m ago

@ComcastJamesH Sorry, forum notifications went to spam and just seeing your note.  Getting 399 Mbps down and 39.1 Mbps up on Speedtest.net app on iPhone 12 Pro.  Following this on phone, got this on desktop (ethernet via Netgear R6700v3 router):  Ping 7, 352 Mbps down, 41 Mbps up.  Sent the Arris SB8200 back to Arris for a warranty replacement.  Should be back in hand today or tomorrow.  My plan is to see if swapping it out again for the Netgear CM1200 makes any different.  If not, the SB8200 goes back into service and the Netgear back to Amazon, followed by another call to Comcast to get this sorted out.

Official Employee

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310 Messages

Thank you so much for your response and the additional information @BobH2015 we really appreciate it! We'd be happy to take a closer look at your equipment and run through some troubleshooting steps to help determine the best resolution. Can you please send us a message by searching 'Xfinity Support'? You can initiate a chat by accessing the chat icon in the top right corner. 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Visitor

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60 Messages

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Visitor

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60 Messages

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Visitor

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60 Messages

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Visitor

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60 Messages

It looks like you have attempted to post some personal information in our public forum. We have suppressed that information to keep your personal data private. Please review our Forum Guidelines below for additional information as to the type of information we want to help you protect: https://forums.xfinity.com/t5/Guidelines/Xfinity-Forum-Guidelines/td-p/3115028

brintonh

Contributor

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33 Messages

6 m ago

@steagallcraig That's what the tech on the phone said when the Comcast tech was here.  "Our advertised speeds are based on testing on our equipment.  Your SB8200 might not hold the whole boot file."  Kinda made sense until we used the Xfi modem/router device from Comcast.  I kept it for 3 days on the off chance that firmware updates might take 1-2 days to push, checking speeds at various times during the day and night - about the same speeds as the SB8200.  Got better speeds with the Netgear CM1200.

jlavaseur

Problem Solver

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615 Messages

6 m ago

@Bobh2015 I have a IPhone 12 pro max , one thing i have found, its distance sensitive, close to the router, amazing speeds, about 20 feet away speeds cut in half, also i have found the bandwidth setting on your router has to be tailored to your environment for the best wifi, more is not always better

(edited)

scraig2

Contributor

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60 Messages

6 m ago

@BobH2015 I did the same thing with my SB8200, sent it back for warranty. Got the new one up and running, same issues of slower speeds than normal. Of note.... when the modem had the original boot file, my speeds were incredible. I was getting close to 1GB wired and 820mb wireless with my S21. The update gets sent and my speeds go back to 800 wired and 620 wireless. My guess is you might see a difference when you get the new SB8200, but once it updates to the new boot file, it will go back down. Also, pay attention to your upstream power levels with each version of the boot file. I know it seems crazy and everyone on this board will tell you it doesn't work that way..... my speeds dropped when the power levels dropped. Keep us posted, I have seen this issue for a year with nothing resolved. 

brintonh

Contributor

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33 Messages

6 m ago

@steagallcraig I'll post the results and the power levels I see.  I'd love to see 800 Mbps wired.  My speed spikes briefly to ~700 Mbps then consistently drops back into the 300-500 Mbps range.

Official Employee

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310 Messages

Good morning @BobH2015, our team would be happy to investigate your connection concerns. Can you please send a message to Xfinity Support so we can run through some troubleshooting steps and take a closer look at your equipment and signal levels? 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
brintonh

Contributor

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33 Messages

6 m ago

@steagallcraig Explain "original boot file then update" statement.  My understanding is that when you hook up the modem for the first time and "activate" by going to the xfinity.com/activate URL, that provisioning updates the SB8200 to the latest boot file and firmware.  I'm not understanding what you mean by "original boot file."

brintonh

Contributor

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33 Messages

6 m ago

@ComcastAlyssa I'll try to do in a bit, after conference calls.  I can't take down my network (two WFH people on the network) with modem resets, etc.

Official Employee

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310 Messages

Thank you so much for your response @BobH2015 and we completely understand! Please send us a private message at your earliest convenience so we can better assist. We're available here 24/7 and happy to help whenever you are ready! 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
brintonh

Contributor

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33 Messages

6 m ago

Glitch in Xfinity Forum!  When I pulled this back up, I got a screen asking me to confirm my registration.  It WOULD NOT accept BobH2015 as the User Name.  The instructions said "Three characters with upper and lower case, numbers and special characters" and any attempt to use "BobH2015"  was rejected.  Similarly, three character user IDs were also all taken.  I mistakenly listed another user name and it's now set with that brintonh.

jlavaseur

Problem Solver

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615 Messages

6 m ago

I got the same message, i just agreed and all is well, but i dont have those characters

brintonh

Contributor

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33 Messages

6 m ago

Tried everything, including just accepting and no go.  Ended up with a new ID.

scraig2

Contributor

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60 Messages

6 m ago

where did my comment go? @brintonh i responded but looks like they took it down or it didnt post. i will get back and explain when i get time from work. 

brintonh

Contributor

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33 Messages

6 m ago

@steagallcraig Sent you a DM.  I see that your message isn't here but it was in my email notification.  Sounds like your issue is the same as mine.  Tech changed every fitting, ran a new wire from pole to tap at back of the house.  Checked speeds and power/noise levels at every point, including at the modem (i.e., disconnected coax from modem and hooked up his device).  All levels were great, no noise on the line (my modem line is a direct off the splitter at the back of the house - no cable TV on the line) so he wasn't sure what the issue was.  Got another tech on the phone who suggested the boot file issue with the SB8200.  But as I said to one of the Comcast support folks above, I've now used 3 modems - SB8200, Xfi Gateway and Netgear CM1200.  By far, the Netgear is getting me the best speeds.  At the time with the tech visit, I had both the SB8200 and he brought in the Xfi from the truck.  Both had almost identical output in the low to mid 300's down.  Both got ~40 up.

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