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Need help with a new upgrade to 400 Mbps Internet speed, but still only getting 120 Mbps.

RobComRobCom Posts: 12 ✭✭✭
edited September 25 in Connectivity Sep 21, 2020

Hello everyone, I hope someone can advise me on how to get my speeds up on my internet.

Today we upgraded to the 400mbps internet speed, we had the standard 120 for a couple of years now, The tech restarted the modem after the upgrade and yet it still is only pulling 120mbps down. I have tried resetting the modem and my router several times since.

I replaced the cables from the modem to my ASUS RT-N66U router, and then after that didn't work, exclusively from the modem to my pc with cat 6 and still the same, I checked the intel gigabit nic and it's running at 1.0gps. Some of the details are:

EVGA home built PC Z390 Dark board

Intel I210 Gigabit Network Connection reporting a link speed (Receive/Transmit) 1000/0000 (MBPS)

ASUS RT-N66U router

  • ·Up to 900Mbps Wireless Data Rates
  • ·2.4 GHz and 5 GHz Concurrent Dual-Band
  • ·Four Gigabit Ethernet Ports
  • ·Detachable High-Powered Antennas
  • ·Two USB Ports
  • QoS disabled

Arris TG1682 modem (Spectrum equipment)

I have no idea whats going on, it should just work.

any ideas?

Best Answer

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    edited September 21 Sep 21, 2020 Accepted Answer


    Something somewhere is causing your modem to scream back to the CTMS... 4 atdma channels at 5120 rate should not be getting that high... Arris spec typically puts that limit @ 51. Surprised it hasn't rebooted yet with it hitting 52.5.

    If the tech padded the line because he/she was getting high downstream numbers, that pad may have also reduced signal on the return side, which could cause the modem to increase output level trying to compensate. If that pad could be removed, it may stabilize a bit after reboot.


  • misterjmisterj Posts: 107 ✭✭✭✭
    Sep 21, 2020

    RobCom, please post a screenshot of the levels/SNRs as seen on the modem Status page. Thanks and enjoy, John.

  • RobComRobCom Posts: 12 ✭✭✭
    Sep 21, 2020

    Hello misterj, thanks for the assistance.

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 21 Sep 21, 2020

    Does anything look out of place?

    Here is the revision: I read somewhere that the modem should be DOCSIS 3.1 and not 3.0, but I have no idea if this is true or not.

    ARRIS DOCSIS 3.0 / PacketCable 2.0 Touchstone Residential Gateway

    HW_REV: 8

    VENDOR: ARRIS Group, Inc.


    SW_REV: 9.1.103J6TW2.SIP.PC20.TW

    MODEL: TG1682G

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    edited September 21 Sep 21, 2020


    Upstream power level is too high... noisy line may be interfering with the modem's time slice request cycles.

    May also want to verify they have you flagged properly in the system for the 400 tier.

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 21 Sep 21, 2020

    The tech was just out here yesterday and ran a test on it, he replaced a "gold" splitter that was causing the power to be too high, he told me that the high power was causing my to internet to occasionally go on and off. He replaced all the ends and splitters, and checked the power with his tester both coming into the house, and at my modem. Said it was right on target.

    The internet has been working flawlessly ever since. (since 8:30 am Sunday)

    Then last night we upgraded to 400mbps, and they reset the modem from the office, but it just doesn't seem to be working.

    Could the tech have been mistaken? If so, what would be the solution? New Modem?

    PS: Thank you for taking the time to assist.

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 21 Sep 21, 2020

    Also, the cat 6 cables I have are very old, (10 years or more) so I ordered 2 new ones from Prime to test, should be here tomorrow.

    Not sure if that will help, but gotta eliminate everything I guess.

    PS: I'm on hold for Spectrum Tech Support now,

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 21 Sep 21, 2020

    Interesting, I may have to call them back here and re-check everything (keeping this info in mind), I noticed my TV signal sputtering a little last night, I wonder if that could be an additional side effect? The tech guy said when he first checked it it was up to 53-54 which he said was WAY to high, all caused by that "gold" radio shack splitter.

    OK, update, I jut got off the phone with Tech Support and I have some information.

    The signal Spectrum sends out is not 400 on the dot, it's much higher, like 550 or 600mbps, she said this accounts for anything the signal might run into and usually balances out at 400mbps after going through all the lines and equipment.

    HOWEVER, my Arris TG1682 modem will handle ONLY "up to" 400mbps, not anything above that.

    she said my signal may be more toward 600 and thus causing that power to be higher, and the modem can't handle the extra power so it just drops back to what it can handle.

    She said I need a new modem (she said my router is fine) and they are sending one out for us.

    (odd that the tech support guys/sales people don't know this??)

    Also, it appears that there are several (3 I think for now) models (brands) of new modems, and the only distinction you could look for is that the number of the modem(s) should start with "E31" and they handle up to 1g speed.

    SO, they were out of those "new routers" right now, lol, so they will ship one to me as soon as they have one.

    PS: It was also noted that this confusion happens "way too often". Sooo, Spectrum might want to do something about that....

    THANKS GUYS!! You guys feeding some info here truly helped me understand this mess a lot better!!

    Problem solved eventually....I hope.

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 21 Sep 21, 2020

    I just had a whole post describing what the tech support told me, and it got deleted somehow!!

    Anyways to sum up, I called Spectrum tech support and told them about the modem status, it turns out that this happens a lot, WAY too often in fact.

     It turns out that the signal that Spectrum pushes out is HIGHER than 400mbps, it more like 550 to 600mbps, this “typically” balances out to an average of a full 400 after going through all the lines and equipment, and my Arris TG1680 cannot handle ANYTHING over 400mbps, so it’s choking on the power/speed. THIS is so spectrum does everything they can to ensure the customer gets the full speed of what they are paying for.

    (It amazes me that the techs and sales didn’t know this…)

     They are sending me out a new modem, of which there about 3 different brands, that will handle up to 1G,  and she said this should clear it all up. She said my router should be no problem and I should get a discount for not using their wi-fi/router.

     The new 1g modems (whatever brand) all share on common thing, in the model number there should be “E31”.

     So, I have to wait for them to send me one, they appear to be out right now, and I will test it then.

    IF I still see those high power numbers when I get my new modem I will call tech support back and give that info you gave me RAIST5150

    I TRULY appreciate the help y’all, I think I fully understand now.

  • misterjmisterj Posts: 107 ✭✭✭✭
    Sep 21, 2020

    RobCom, your levels/SNRs are not just fine, they are great! Please look at the errors! "(It amazes me that the techs and sales didn’t know this…)" I suspect they do not know this because it is not true! Your modem is more than capable of handling what your ISP is pushing. Your new modem is a DOCSIS 3.1 and I have the Ubee version. You will not be able to look at the statistics inside. Please hold on to the old, you may want to use it later. I think you will be charged for the router the ISP will send you. Thanks and enjoy, John.

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    Sep 21, 2020

    Hate to say it... bit that sounds more like some CYA speak.

    In the 3.0 space, timeslicing usually works out to around the equivalent of 8 to 20mbps per channel, depending on how saturated nodes get. Technically, just over 38mbps of bandwidth per channel is shared (just over 1200mbps across 32 channels). Everyone gets time slices divvied out to them for the send/receive windows they request. 400mbps is about a 40% load at 24 channels, 33% load across 32. 120 with 24 channels is about a 12% load... at 32 channels, it is around a 9% load.

    With 24 channels locking, they should easily be able to provide 200mbps unless those 3.0 spec channels are HEAVILY saturated. Capacity may have been oversold in your area, as it sounds like they may be relying on the OFDM channel in the 3.1 spectrum for the 400 tier and not just gig service.

    Or something just went sideways on them, and that is the work around they are putting in place.

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 21 Sep 21, 2020

    Well, we will find out when the new modem gets here, and if it's not right I will just have to deal with it some more.

    At least I will know it's not my router or my cables by then ...lol

    "Your new modem is a DOCSIS 3.1"

    actually it's telling me it's a DOCSIS 3.0, and it's a older modem , got it 4 or 5 years ago. the tech never replaced the modem, he removed some bad splitters and replaced all the end connectors to make sure they were all new, he said my modem should be fine.....

    BUT, keep in mind about the tech guy, he was out here checking the lines BEFORE I upgraded, so, not sure if that had anything to do with the power level he checked "at the time" or not. To be fair, he really seemed to know his stuff.

    I will let you guys know what happens, this should be interesting.....

  • RobComRobCom Posts: 12 ✭✭✭
    Sep 21, 2020

    Oh and by the way, THANK YOU for helping to educate me, this will help if I have to call them out here again.

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    edited September 21 Sep 21, 2020

    No worries mate. The whole system is in a state of flux these days. Some markets can't get approved modems to work reliably that are rock solid in other markets.

    Some serious growing pains going on... don't think Charter was quite ready for the nightmare they signed on for with the merger. Some of these lines have been in service since the 70's/80's... when cable made a HUGE push, finally expanding throughout the south.

    Just keep the communication going with them. A large part of the problem is them not knowing where the hot spots are that need work. The more people calling in with problems, the more quickly they can track down the problem segments.

  • misterjmisterj Posts: 107 ✭✭✭✭
    Sep 21, 2020

    RobCom, please look again - I said "Your new modem is a DOCSIS 3.1...". Good luck and hang in there. Enjoy, John.

  • RobComRobCom Posts: 12 ✭✭✭
    Sep 22, 2020

    Ok you ready for this!!

    I got 2 brand NEW 550mhz Cat 6 cables and hooked up my existing router, and you WERE BOTH RIGHT!!

    Same modem is now doing this:

  • RobComRobCom Posts: 12 ✭✭✭
    Sep 22, 2020

    RobCom, please look again - I said "Your new modem is a DOCSIS 3.1...". Good luck and hang in there. Enjoy, John.

    Humm, I'm looking at my modems HW/FW Versions and I'm seeing this:

    BUT it's working!!

    So question, for my own edification, how did you know it was a 3.1 even though it says 3.0?

  • RobComRobCom Posts: 12 ✭✭✭
    edited September 22 Sep 22, 2020

    ONE more question if I may pick y' all's brains again?

    Should a CAT 5E cable work through my ASUS router? I have a 50ft CAT 5E cable right now going to one of my bedrooms, and am only getting 90 down but I am getting 23 up?

    Should I run ALL NEW CAT 6 cables?


    PS: NOTE the cable I replaced that made the difference was a CAT 6 cable, but I have no idea how it was rated for mhz, and it's about 10 years old, so there IS a difference in CAT 6 cable types?

    PPS: Also, they are still sending me out new equipment (modem) so I'm wondering if I would hook that up and see what it does when it gets here OR should I keep this one??

    And thanks again!!

  • misterjmisterj Posts: 107 ✭✭✭✭
    edited September 22 Sep 22, 2020

    RobCom, I was previously talking bout your new (to Be) router being a 3.1. The 3.0 Modem with 24 channels, your levels and SNRs should support 400 Mbps (up to 1000 Mbps) just fine. So should Cat 5E cable if it not beat up or too long. I think it is rated to 100 feet. Cat 6 is a better and will support up to 10 Gbps. Please see here. You are looking good. Your choice to go with the new Modem or hang on to the old one. Either way, you can always get a Spectrum modem if the one you are using dies. If you use the Spectrum one, be sure to keep the old one handy. It always comes to the rescue when needed. Thanks and enjoy, John.

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    edited September 23 Sep 23, 2020


    You likely had a signaling issue on the Spectrum side of the modem that has since been resolved (ie, the high upstream power level earlier is one indicator of a potential noise issue). Should be able to verify that if you look at the signal page.

    Granted, you could also have issues with the ethernet cables. The wires inside are pretty thin (24ga in 5e, 23ga in 6). 5e doesn't always have the best insulation... doesn't take much to compromise them. Just losing one wire in a twisted pair can cause big issues. I kid you not... I have stripped and put new ends on cat 5/5e without using a knife/scissors. Literally just an angler's tool in my pocket and a bag of ends--whacked off the bad end with the wire cutter/pliers and used my teeth/nails to pull the jacket back, line up the wires by color and slipped them in a new end to be crimped down... yeah, they can be pretty flimsy sometimes.

    As to the 5e or 6 debate... both can handle up to 1ghz up to about 300 feet (100 meters). CAT-6 is better insulated and such so is better when dealing with higher frequencies, long pulls etc... can go up to 10gbps on a decent length. Cheap ones can still get flakey at about 40/50 meters or so at that bandwidth. but 5e can only pull it off in short runs, like around a server room kinda thing.

    That long run may have an issue with one or more of the pairs, especially if it is also about 10 years old. Either class should work for about a 50ft run... just need to make sure it is of good quality. Going cat6 should give more assurance on that front because of the thicker insulation and slightly thicker wires inside, but either should work provided they are a decent build.

    As for the modem issue... they may not take kindly to you just holding on to their modem. Can hold out a bit to see if things remain stable and send theirs back if they do. It is kinda nice being able to check the stats like you can with your own modem. But if it flakes out again on you in the next week or so, contact them to register their modem and keep an eye on the performance.

    Should note here that this is where some markets are having problems with some modems going screwy--the 3.1 space. The transition to using the 3.1 specific channel space is proving problematic in some areas. So it MIGHT work out better to roll with a 3.0 modem while still using a 3.0 bandwidth tier.

    If it goes unstable again on their modem, get them on the phone ASAP so they can look at the stats right away. Do NOT reboot the modem for at LEAST 6+ hours before any tech visit... or even to call it in if you can. Rebooting can clear logs, reset channel assignments, and zero out error counts. Want to preserve that information for them to review it.

    Keep that 3.0 modem around in case they start and continue to have issues with that modem they sent you. It might be handy as a test case if they too are having issues specifically with the OFDM channel space that new modem will try to use.

  • pdqneonpdqneon Posts: 1
    Sep 24, 2020

    I had the same problem. Support said not to use port 1 on the router, it is set to limited bandwidth. I plugged into port4 and away I went.

  • karlbeckmankarlbeckman Posts: 2,221 ✭✭✭✭
    Sep 25, 2020

    Need to correct some comments about CAT-5e cable ratings: ALL CAT-5e cables are spec'd to support Gigabit ethernet connections at lengths up to 100 meters (330 feet). That said, there are still cheap and defective Chinese import cables out there, so spend a few pennies more and buy the good stuff. No need for CAT-6 which requires special grounded connectors and shielded 4 pair cabling, not UTP.

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