I swear … this will be my last Left 4 Dead 2 post until the next one. In any case, yesterday afternoon me and some of my zombie killing buds got together to play the game on the XBox 360. After some time, the game became unplayable because of lag. Zombies would stutter across the screen and by the time I fired a round, the zombie was gone and/or replaced by one of my buds. Sometimes I’d walk a few feet, then warp back to my starting location, or appear in an entirely different room all together.
Last night, we discovered the lag had only grown worse, making me suspect that the issue was due to server load as opposed to a poorly coded game. We decided to give it another go, and while setting up the game, I noticed that I could switch the game from a “official dedicated” server to a local host. What that means is that instead of connecting to a dedicated Valve server, my own XBox would be acting as the server. In theory, this sucks since I have the speed advantage and if I leave the match, the game either stutters as a new server is located, or the game just dies (like Team Fortress 2). Usually dedicated is the way to go, but I’m guessing those servers are swamped as people play the game. Thankfully, Valve had the foresight to add the option so with the flick of a switch, the game went local and the lag vanished. Granted, we only played co-op so an additional four other players may induce slowdown, but at least you can play.
Lesson of the story — switch to local to avoid the lag. When the load on the dedicated servers normalizes, switch to the dedicated mode. But above all … kill all zombies!
UPDATE: This appears only to work for co-op. For versus, you still have to use the dedicated mode, which as Greg points out below, is still busted.