NETGEAR CM1200 Stuttering and freezing while playing games (XFINITY)

[ashkb19]

Issue: Having major stuttering/freezing and unstable connection issues while playing online games. I don't experience these issues while streaming (presumably because of buffering) but it has made these games unplayable even with decent speedtests for my internet - ranging from 250-315 MBPs. 

Setup: Netgear CM1200 wired to an Asus RT-AX3000 router. Ethernet is wired to the router as I can only use one ethernet port on the modem for some reason. I'm attaching the modem cable information below (not savvy with this part) as I've seen in other posts like this that this could be a culprit.

 

[FURRYe38]

What happens if you power OFF the modem and connect your gaming device directly to the modems WAN #1 port, then power ON and check your gaming? 

You'll have to contact the ISP and ask them for support on the additional WAN Ports of the CM1200 modem. This are WAN IP address assigned ports that come from an ISP. These are NOT LAN ports thus there is NO router build in to this modem. 

If there are problems seen with the gaming device directly connected to the modem with out the router:

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 

https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...