SB8200 is compatible with 500 Mbps speed plan so to isolate the issue could you please confirm the following details

Perform speed test on the device connected to the modem directly without router.

What ethernet cable you are using for direct connection?

Also check for the cable signal level mentioned on the modem GUI by following the steps mentioned on the below article.

http://arris.force.com/consumers/articles/General_FAQs/SB8200-Cable-Signal-Levels

Thanks for your help.

I connected the computer directly to the modem and also rebooted the modem by disconnecting the power cable for 60 seconds.

My ISP is Optonline and I am on the east coast of the USA.

I connected to the EWEKA server in New York, NY. for the speed test.

Download speed was: 467.34 Mbps

Upload speed was: 35.02 Mbps. 

I’m using a Vandesail Cat8 Ethernet Cable 2m, High Speed Network Cord Cable, RJ45 LAN STP 40Gbps Cat 8 Patch Cable.

Logging into the modem interface I find what might be a problem as all of the Downstream Bonded Channels are between + 15 and +17.

Under Downstream Bonded Channels channel ID I see the following….

First channel listed is 28.

Then in order, 1 through 27 and then 159.

SNR Levels are 37.8 through 42.0.

Upstream Power Levels are between 37.0 dBmV and 39.0dBmV.

Based on the article you listed it looks like I should perform a factory reset for the modem.

I’ll wait for your verification before I do that.

Thanks again.

Regards, 

Dmin11

Well, it’s been 11 days, as anyone can see, since I answered the questions asked by the mod. Still no answer back. I thought I would update this thread for anyone who comes buy to look for answers.

As of today, I have completed a factory reset. Still connected directly to the modem. After the reset my speed was minimal until I rebooted the modem. Now I am up to the 500 mbps . The problem has always been, however, that the speed reverts to 100 mbps after an irregular time interval. So, I contacted my provider in an attempt to reset the line connection information. I just finished a chat with a rep who refreshed the line information for my address. The modem numbers that I listed above have not changed. I will be checking daily to see if my speed holds or if it once again reverts back to 100 mbps . I’ll post if it reverts back. If my speed is still good after 2 weeks, I’ll also post to update and finalize this thread.

Regards, 

Dnmin11

I apologize for the delay in responding. Could you let us know after the factory reset, have checked the cable signal levels?

Before factory reset, upstream power level is not in a range. If the same after factory reset, please contact your internet service provider and ask them to adjust the cable signals within a range.

Please keep us posted on the update.

Thank you.

I have the identical problem--am paying for 300MBps, but every few weeks or so, my download speed reverts to 90 MBps. When this happens, my “cure” is to hard reset the Arris 8200. While not a particularly elegant solution, at least it is enough of a workaround for me to keep things running at paid-for speeds. The random slow speed problem began in roughly February 2024 when Xfinity allegedly did a system “upgrade” in my neighborhood. Since then the problem recurs every few weeks, and I have made multiple service calls to Xfinity. On the last visit, a very savvy Xfinity tech diagnosed line levels in detail and found nothing at fault. He then noticed that he was unable to properly read a file that has to do with provisioning data (I have no further details). He did not know why the file becomes corrupted, but speculated that the bug causes the modem to revert to a default minimum speed when it can’t properly read the provisioned data. Overwriting the corrupt file via a hard boot makes the problem go away, but in a few weeks it’s back again. The tech said that he would report the problem, but that it was unlikely to be addressed very quickly, because it’s not a hardware issue, and that there are multiple parties involved. He suggested that I could continue with the reboot workaround if not too inconvenient, or else buy a modem from a different brand if I wanted a quick and permanent solution. Though I dislike having to toss fairly new equipment, I appreciated that he found a consistent workaround, and I do think that a different modem manufacturer will be my shortest path to permanently correcting this issue.

Could you let me know whether you are experiencing slow speed through direct connection or while connecting with any router.

I also suggest checking the cable signals to make sure all signals are within range.

http://arris.force.com/consumers/articles/General_FAQs/SB8200-Cable-Signal-Levels