Speed/downstream issues (Gig service w/ SB8200)

[Psychor]

This week I moved from an Arris SB6190 to a SB8200 modem due to upgrading to gig service. The modem was purchased new and was confirmed supported by Comcast. The main Comcast line to the house is directly connected to the line inside the house - no multiple-way splitters are in use.

While my upload speed has improved, my download hasn't changed and is ridiculously slow. I might hit ~500 Mbps down for a second and then it’ll stay around ~190 Mbps. I’ve factory reset and power cycled the modem. I’ve asked Comcast to re-provision the modem and I confirmed with them that they programmed it correctly from their end.

I performed the attached speed test by directly connecting my laptop, with a gig port, to the SB8200. I've also attached pictures of the stats of my modem along with downstream and upstream values.

I've called Comcast numerous times and all they want to do is reset the modem remotely.

Any idea what the heck is going on?

[EG]

You have a TERRIBLE connection !! Some stuff that you can try;

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.

[Psychor]

As I mentioned above I don’t use splitters. Are there any Comcast reps on this forum that we can direct this post to?

Thanks.

[EG]

O/k then please re-read my last comment. 1800comcast. Good luck !

[Psychor]

Tech is coming tomorrow. Will update.

[EG]

Show them this thread if you will. Again, good luck with it !

[Psychor]

I was able to resolve the issue.

1. For whatever reason the one-to-one grounding block I had was causing issues. I replaced this with another one that I had in the house and my speeds hit 900+ Mbps down. However, even after that not all of my modem channels were locking.

2. It turned out Comcast had a trap installed on my line. Removal of the trap allowed all channels of my modem to lock.

Hope this helps someone else down the road. 👍🏻

[EG]

Glad that it got straightened out ! Now closing this thread.