When changing fps_max for the dedicated server, there are periods when zombies (and even players) stutter. They move smoothly for couple of minutes, then they start to stutter for couple of seconds. Very annoying.
I'm not sure if the issue is present with fps_max set to default 30.
Using fps_max 30 is not great though, because it makes zombies stutter slightly constantly (which is weird, because L4D2 is smooth with these settings).
No chokes or anything like that, no drop in FPS either. Same thing happens on higher tickrate settings.
I use the same host for L4D2 without issues, I believe it's issue with the L4D1 srcds itself.
Linear Mode
