super low download speeds with my Motorola MB8611

@XfinityWilliam

I'm kinda shocked that this link/forum doesn't support Mozilla: the editing sections are grayed-out, even I was registering, I had to use Chrome

To answer your question: via CAT5e cable.

What I don't understand is why Xfinity speed test scores the lowest bitrate???

So what I found, was to download and install "speedtestbyookla_x64.msi" and test my gateway speed> boom>

Also I tested with NetGear router connected> same speed.

Which tells me that I have an issue with my NIC/system> started troubleshooting my PCI based TP-LINK TG-3269 10/100/1000Mbps> my original built-in dual 1Gb NICs said farewell after lighting stroke my LAN> I ignored to connect my modem/router to the surge protected outlets on my UPS.

This PCI slot has 133 MB/s, so it should easily support 400 Mbps from Xfinity. To answer possible question> there's another StarTech.com 1 Port PCI 10/100/1000 32 Bit Gigabit Ethernet Network Adapter Card (ST1000BT32) installed, but it's not connected via CAT5e. So it doesn't share the bandwidth. In fact, when I tried to connect, got stupid Windows message about Unidentified Network. This is just FYI.

This uses Realtek chipset, so I did put the latest driver's version available (from 2022), even changed the speed under the NIC's settings to 1 Gbps:

Still no luck> tried another cable> same story

Another 2 interesting things:

1. Comcast is having now some sorta outage in my area (but I think it's affecting TV only, per my account info), but by both Downstream/Upstream lights on my MB8611 are solid blue, used to be solid green.

2. I'm kinda curios why my all downstream channels in MB8611 are full of errors:

I added a splitter (to reduce the signal's strength, although it wasn't needed since original data was still under 15dB), anyways I did, random corrected errors, but then Comcast got outage in my area (per info I have) and this is where the lights on modem changed and now the connection is full of both corrected and what's even worse "non-corrected" errors.

This is just something else I found. My main concern is how to make my TP-LINK TG-3269 10/100/1000Mbps transferring at least 400 Mbps. What a puzzle...

@nickteshua Thanks for the additional information. I can understand your frustration especially when you have purchased a new modem, and you're having speed issues. Have you had the time to check and replace your connected devices such as the surge protector, splitter and cat5 cable. Three years is a long time to have speed concerns. With all those additional devices connected have you tried to run a speed test just to the modem and disconnect everything else? The reason we are asking is to see the speeds your modem is pushing out before it goes to Wi-Fi. 

I would like to access your account to see the plan you're ok and troubleshoot your connection. 

Can you please direct message me your first and last name along with your full service address so that I can assist you further?
Here's the detailed steps to direct message us:
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@XfinityKei . I already mentioned that I get the same results either with router connected or direct modem>PC connection. I don't have any Wi-Fi devices at the moment. Actually, I 'm gonna try the speed test via USB Wi-Fi adapter and see if I can get 300 Mpbs (my Netgear's max output)

Also I already posted a screenshot with the Gateway's speed (either modem or router), please see above

I went on YouTube> played with the MTUs/registry settings/static IP/alternative DNS> barely can squeeze around 160Mbps with Speakeasy Internet Speed Test - Check Your Broadband Speed | Fusion Connect or Speedtest by Ookla - The Global Broadband Speed Test

Xfinity speed test as always> barely gets 60-80 Mbps. I spotted only once 120 Mbps. but right after it dropped to 20/10/0. I just don't get if Xfinity does it on purpose or what?

So, what I did: ordered 2 CAT6 cables (but as IT tech I'm almost 100% positive, this isn't not the cable's issue, since I already swapped for another 5e which came with my Motorola MB8611).

I also ordered brand new PCIe 2.5 Gbps network adapter for my x1 slot. It should easily get me over my Comcast's 400 Mbps plan, since the speed of PCIe x1 slot is 225 MB/s, which brings to 2 Gbps.  My PC is kinda old, but still it has 2 NICs 1.0 Gbps + 1 PCIe x1 (the other is covered by video card) capable of 225 MB/s, so for no reason I shouldn't be getting 400 Mbps. Period.

I have pretty solid hardware config, even though it's kinda aged.  So it should easily handle 400 Mbps

@XfinityKei> to answer your highlights:

1. surge protector: all my network gear is plugged into my CyberPower 1500 va (properly surge protected), so this isn't not the case

2. splitter> this isn't not the case since I've already tried and mentioned: no difference with or without. Only difference is> without splitter the signal for Downstream channels goes up to 10 dB, for Upstream channels goes a little bit down. But it doesn't affect the downstream speed. Upload speed always remains the same, at around 12Mbps (my plan stands for 10Mbps)

3. and cat5 cable> not the case, already mentioned that it was swapped for another one

@XfinityKei> How will I get hold of you via Xfinity Support? I'm just fed up with all previous clueless Xfinity agents, both real and virtual

update:

1. added 2.5GBase-T PCIe Network Adapter RTL8125B 2500/1000/100Mbps PCI Express Gigabit Ethernet Card

2. replaced with CAT6 cable

3. removed splitter> download signal went up, but is still within the range (-15dB +15dB)

No idea why I'm flooded with both corrected and non-corrected errors. Adding splitter doesn't make a difference> same whole pile of those errors

Event Log

Time    Priority    Description      06:55:33 Tue Jan 23 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     06:55:37 Tue Jan 23 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     06:55:37 Tue Jan 23 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     06:55:37 Tue Jan 23 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     06:55:38 Tue Jan 23 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     06:58:00 Tue Jan 23 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;     06:58:26 Tue Jan 23 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];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=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;     19:50:38 Wed Jan 24 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];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=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;     19:32:20 Fri Jan 26 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"]CMTS-MAC=[Edited: "Personal Information"];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=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;     Time Not Established   Notice (6)   Honoring MDD; IP provisioning mode = IPv6     21:07:43 Sun Jan 28 2024   Notice (6)   DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     21:10:00 Sun Jan 28 2024   Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=00:90:f0:7b:04:00;CM-QOS=1.1;CM-VER=3.1;     21:10:27 Sun Jan 28 2024   Notice (6)   CM-STATUS message sent. Event Type Code: 5; Chan ID: 14; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     21:15:16 Sun Jan 28 2024   Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:02:55 Mon Jan 29 2024   Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:03:07 Mon Jan 29 2024   Notice (6)   CM-STATUS message sent. Event Type Code: 2; Chan ID: 12; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:03:08 Mon Jan 29 2024   Warning (5)   MDD message timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:03:18 Mon Jan 29 2024   Notice (6)   CM-STATUS message sent. Event Type Code: 5; Chan ID: 2 12 13 14 15; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:03:25 Mon Jan 29 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:03:25 Mon Jan 29 2024   Warning (5)   MDD message timeout;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:14 Mon Jan 29 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:15 Mon Jan 29 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:16 Mon Jan 29 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:16 Mon Jan 29 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:16 Mon Jan 29 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:17 Mon Jan 29 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:28 Mon Jan 29 2024   Notice (6)   Honoring MDD; IP provisioning mode = IPv6     05:04:38 Mon Jan 29 2024   Notice (6)   DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;     05:04:46 Mon Jan 29 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;

4. NIC's driver has been updated

Tested speed after that> same [Edited: "Language"] download speed

@nickteshua Thank you for all of that information. Have you used the Xfinity app to troubleshoot? To learn how to troubleshoot in the future you can follow the link: https://www.xfinity.com/support/articles/using-xfinity-app. Honestly, it is the best app to date that we offer and super easy to use.