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smurficus's avatar
New Contributor II

Diagnose Slow Download Speed

Hey! I was wondering if you could assist me in diagnosing my slow download speed:

The moment my cox service went online, everything was great: 300 down / 30 up. Even my wifi was at 300 down.

About 1 day later, and the days following, the connection has been much slower ~ 20 - 30 down / 30 up

One day, i had reset the modem (SB6190) so many times and stopped connecting entirely. I had to reset my modem to factory settings, and I was able to get back online.

I have tried hard wired to the modem, no router, probably every day, hoping something on the cox side would resolve.

I have tried a different coax connection from the wall to modem with similar results.

With the 30 mbps download, I'v noticed that my SB6190 status screen ( shows a "Correctables" column. In this column, there are only 2 channels with much higher "Correctables" to the order of X10. Assuming that these are the only two channels pulling their weight, is this most likely my router or ISP?

I'm suddenly on a pretty tight budget. Would it be free for a tech to come out and swap my modem just my modem? Or would it be more cost effective for cox just to check out the ISP side of things?

  • The issue has been resolved with no change on my end.

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  • grymwulf's avatar
    Contributor II

    Correctables+Uncorrectables should be no more than .04% (long-term) of the total frames pushed through each channel.

    You will usually see a spike higher than that when a modem is first connected, push some data through and check it a couple of minutes later.

    Swapping modems can usually be handled at a cox location on rented modems.  If you own it, however, it is yours to deal with returns/exchanges.  If you are suspicious of it being the modem, stop at a store, ask to rent a modem - bring it home install it and see.  If it fixes the problem, you are golden, and can decide what you want to do from there.  If, however, it doesn't fix the problem, just return the modem to the store and you will only be out a day or two of rental fees.

    Since you are using a Surfboard modem - head over to - it is the diagnostic page for that modem. 

    I'm not going to go into what I consider to be good signal levels, but you can check out this FAQ here:

  • smurficus's avatar
    New Contributor II

    renting a modem for a few days is a great, cheap way to diagnose if it is the modem! Thanks!

  • AllenP's avatar
    Valued Contributor

    The SB6190 is a modem, I'm not sure Cox still rents modems.  The Cox price list in my market only lists gateways (listed as "WiFi modem, dual band").  smurficus, if you must rent a gateway, don't connect your router to it, connecting a router to a gateway can result in problems.  Also, make sure all cable connections are secure and tight, bypass any splitters in the line.

  • smurficus's avatar
    New Contributor II

    The issue has been resolved with no change on my end.