New modem. Gateway reports packet loss, jittery latency

I’m getting laggy, jittery performance on my home internet from Comcast lately. I just upgraded my modem to an Arris SB8200 to replace an older arris modem that was supposedly on EOL according to Comcast. Ever since upgrading I’ve been having sporadic but repetitive spikes in packet loss and latency. Every 5 mins or so I get a huge spike in packet loss, >50% according to my routers gateway monitor. However, if I send a bunch of pings to Google, or whoever I get some jittery latency, high RTTsd, but no packet loss or at least not nearly as high. Though all the while the gateway monitor in pfsense is still reporting 30-50% packet loss. What’s the deal? Not enough pings to capture the packet loss?

I tried connecting a pc straight to the modem to cut out the router in case I borked some settings in pfsense and I’m seeing ~40% timed out pings when I send out endless pings from cmd in windows 10.

Checked the modem status and everything seems fine, good, uniform downstream power and signal across 28 downstream channels. Did a factory reset on the modem, no changes, still sporadic performance.

I have no idea what’s going on, but I’m getting really choppy, dropped connection and it’s getting old. Comcast is coming in a day or so but I thought I’d try to figure it out in case I get a not so knowledgeable technician.

Is there something else I can do to start diagnosing the issue further myself?

Do you still have the old modem? Can you test with it again? That would at least give you a hint if it’s the modem or the connection because…

'nuff said.

Question if it is the modem, the connection, or the combination of both.

I dont know the modem but it maybe a good idea to check if there is a firmware update available.