I'm having the exact same situation. I've got the Gigablast service, I also have the Surfboard 8200 and like you I've had no issues over the last few years since I upgraded. I'm using a 3 month old TP Link AX6000 router so I didn't think that was the issue. My 8200 however, is 3 years old. I started noticing it first with my WiFi but didn't think much of it since it wasn't horribly slow and there is nothing using WiFI that requires a super fast connection (phones, 2 laptops Google home devices, ring doorbell and camera and a couple of Roku's that are rarely used). I did notice one Roku was taking longer to load but experienced no issues once connected. Then last week everything changed. I was working and my laptop became extremely slow, ran a speed test and it was barely reaching 10 mb. I then tested the WiFi on my phones, same deal. I did switch to the 5ghz band and it improved quite a bit. The computer I was using is in the same room as my old router that is now being used as an AP. it's connected by a long cable to the main router so I plugged my PC into the AP and speeds were normal. OK, so I'm thinking it's a router issue. Did all the troubleshooting, rebooted and reset, no change. Left it alone, had to go to work. Came home that evening, I have a Nvidia Shield and a Roku Ultra connected to the router via ethernet. The Shield would no open HBO and was slow on other steaming apps. Ran a speed test on my PC, barely reaching 20. So I rebooted everything, nothing changed. Eliminated the router, connected my PC directly into the modem, a bit better but still only hitting 30-40. Now I know my router is not the issue, tried a brand new laptop to eliminate any PC issues, same deal. Called Cox, they suggested the issue was with my modem. So I went online and purchased a new one, it arrives today. Fell asleep watching TV, woke up at 2, was about to go bed, looked at my PC and noticed I still had the speed test page open. Tested it and got peak speeds over 800 which is normal for the Gigablast service. At about 9 AM, it was getting to 650-700, an hour later 500-600, it's 11 am now, last test was 74!! Hmm,now I'm wondering if the issue is on the Cox side of things. I'll see when I connect the new modem. Let me know what, if anything resolved your issue.
I'm having the same issue with a SB8200. I did a full modem clear reset, which helped, but noticed it started again last night around midnight. Looking at the cable modem log files, it looks like a time sync error where the modem is getting a 1/1/1970 date from the cable service, which then won't connect properly with the Internet service, (access denied error) This is common with computers when connecting to a network. I'm not sure where that date is coming from, but it seemed to resolve again early this morning. Cox, what could be causing this, and what is the solution?
