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[SB8200] Internet is around 15-100 Mbps on 400 plan

Regular Visitor

[SB8200] Internet is around 15-100 Mbps on 400 plan

I just subscribed to Comcast earlier this week with the 400 plan. I moved here last week, and k ow that there was Comcast here earlier before I moved. So no professional install should be required. I also know that my modem, SB6183, doesn't support that 400 plan (at most does 250), but I do plan on upgrading the modem in about a month. Was hoping I could pay for 400, and just get 250 for a month.

I've called tech support 3 times, and gotten 3 different answers.

First time, they said they couldn't do anything, and would just leave it as is.

Second time, said that the speed and bill is linked. I can't pay for 400 and get 250. So he downgraded me to 250, but did mention I had the wrong boot file (which he gave me the supposedly correct one). Still same slow speed.

Third time I called, was told I have the incorrect/older firmware on my modem, and also that I have the 50 plan, and not the 250 plan. Just checked, and I have D30CM-OSPREY- firmware, for what it's worth. He tried to push the updated firmware, which took a 15 or so minutes, but ultimately failed due to slow speed and timeouts. Was advised to call the manufacturer, Arris, to see if they update it...and they told me it was the ISP's responsibility, and that end customers can't do it.

I've uploaded my modem's status page, but not sure what to do at this point. Call tech support for a 4th time and get a 4th different answer? Just trying to get decent internet speed before I upgrade my modem. And I also don't want to upgrade my modem (roughly $200) and run into the exact same issue on the off chance it's not my modem's fault.

Advice? Thoughts?
Diamond Problem Solver

Re: [SB6183] Internet is around 5-15 Mbps

You have some power level and SNR problems going on there. This should be addressed first before anything else.


In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


The version of firmware that you have is identical to mine and is the current one.

Regular Visitor

Re: [SB6183] Internet is around 5-15 Mbps

"If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured..."
No unneeded splitters that I can see; the modem is going straight to the wall. Not sure what's behind the wall, though. I tried the cable I used in my previous apartment with TWC with no issues there, and I tried the cable Comcast sent in the self install package.

" Perhaps it's best to book a tech visit to investigate and correct."
I suppose that's what I'll have to do. Just not a fan of spending $60 when it was working beforehand (I'm assuming; don't know if the previous tenants had issues, but I do know they had Comcast), and I'm fairly certain it's not my equipment's issues. To me, it's almost akin to paying Comcast money to upgrade equipment they'll use to better service the area, and thus be able to generate a higher profit due to better equipment they fall in on, since it stays with the building and ISP, and not customer owned that I'll take with me. So they should foot the bill, in my opinion. Oh well.

Thanks for the help. I'll follow up once I get a tech out here.
Diamond Problem Solver

Re: [SB6183] Internet is around 5-15 Mbps

If the tech finds that the problem is on their (Comcast's) side of the grounding block / demarc point, you won't be charged. Good luck !

Regular Visitor

Re: [SB8200] Internet is around 20-100 Mbps on 400 plan

Well, the tech was supposed to be here yesterday, and didn't show. However, I went ahead and got the fancy new SB8200, which got here today.

Plugged it in, and then called Comcast to have them provision it and upgrade my plan back to 400. Now my speed is 20 on Speedtest or 100 on Fast (I see why they recommend Fast). But both together is still not even half of my plan.

They forwarded me over to tech support, who informed me that: "Automated system has detected that a signal was out of bounds." Guessing that means I still have power and snr issues. Attached a picture of it. They rescheduled my missing tech, so I'll be back after he (hopefully) shows up, lol.

Oh, and firmware is currently D31CM-PEREGRINE- since the last tech (incorrectly) said my older modem had the wrong firmware.

Edit: well, they want to charge me $60 for a professional install since it's been less than 30 days since I plugged in the modem, and they can't schedule it for free because of that. This residence had Comcast before I showed up, so not sure what a professional "install" can do besides plug it in. Troubleshoot non-install related issues, sure, but nothing install related. I was advised to wait 30 days for it to be free, so I guess I'll be back next month after the free tech visit?