Do you see anything in the Event Log when this happens? T3/T4 timeouts? CMTS errors/warnings.

There was one instance looking at the event log right before I noticed it had slowed down. However there was a more telling thing in the event log. The date and time read reverted back to 12/31/1969 the factory default I assume and once I reset it the time/date was correct again along with the speed. I just factory reset the modem to see if that resolves it. If not can I just contact Arris support to request a replacement model since it is under warranty? I want to rule that out before contacting Cox again.

Thanks!

If you see the date/time do that,  it usually means the modern is restating. That's often a signal issue.  I would see if there are T3/T4 timeouts right before that, or CMTS warnings.  If not,  it is more challenging.  You'll need more detailed guidance from the Arris folks. 

Hi namrevil71, did you ever resolve this? I have the exact same issue with my S33 dropping from ~900Mbs to 30Mbs on COX. Except mine does it every few days. Reboot is the only way to fix.

Thanks,

F

If you are experiencing with intermittent internet connection, I suggest you to check the cable signal levels to make sure all the signals are in range.

http://arris.force.com/consumers/articles/General_FAQs/S33-Cable-Signal-Levels

Thanks for the link. I believe they are in range. The upstream dBmV levels look a little low, but I read elsewhere that it ok - that’s all the power COX needs to connect. It seems that COX would request more power if required. Not sure if this is true?

In any case, I actually caught it this morning when something happened to switch the speed from ~900Mbs down to ~30Mbs. When it happened at 09:43:25, my work VPN disconnected and the internet dropped for a few seconds. Here is the event log at that time. The two related events highlighted in RED:

I had checked the levels prior to this event and they were about the same, except for the 32 uncorrectables on channel 160. Here are the current levels right now (only getting 30Mbs down). Interestingly enough, when it happens, it only affects the download speeds. My upload speed always stays around 100Mbs, which is normal.

From past experience it will now stay at 30Mbs down indefinitely, until I reboot it, which I’m about to do. Any ideas would be appreciated!

*EDITED to replace MAC addresses with X.

Thanks,

F.

As I checked the cable signal levels, the upstream channel’s power level is not in a range.

I suggest you to contact your internet service provider to adjust the cable signals within a range.

I'm experiencing this same exact issue. Except I experienced this issue with my old router as well which was a surfboard SB8xxx. I bought the S33 to rule out the modem being the issue. Cox service tech should be out tomorrow to check on things as I have had 10 tech out and numerous calls to tech support (who dont know anything useful) to me, the OFDM channels seem to have a lot of uncorrectable errors when this happens. Cox says signal levels are fine but they seem out of range compared to the link provided earlier. Now I have to convince them this is their problem and not my equipment.