I'm getting spikes of sometimes over 2000 ms, both on Ethernet and WiFi. As a gamer, these ping spikes completely disconnect you from all online games except for Counter-Strike: Global Offensive(because it has a disconnect fail-safe.) I've rebooted the modem many times, only for the issues to come back within hours. I've recreated these issues on both my Xbox and PC with over 20 different multiplayer games. I have no internet speed issues, getting easily over 350 Mbps download on Ethernet and over 100 Mbps on WiFi.
This has been going on for a few months now, with some weeks seeing no issues and others having online games be unplayable.
Any help would be appreciated!