Multiplayer has gamebreaking desync issues

[kit]

Characters in multiplayer will lose synchronization of their location and begin teleporting around until the server is rebooted. It causes zombies, vehicles and doors to behave spontaneously. These issues have been present for at least two full years.

Fixes we have attempted (none of these resolved the issue):

• removing every single mod
  
• circumventing steam relay using direct connection with steam disabled
  
• using a dedicated server instead of in-game hosting
  
• playing over LAN with <10 ping
  
• playing on a new machine with overpowered hardware
  
• playing with extremely low zombie population
  
• removing all weather effects
  
• reducing all graphical effects
  
• greatly expanding the game and server's RAM allocation
  
• hosting dedicated server on a separate machine with no game client running

Once this issue manifests the other character's position cannot be tracked on my screen despite sub 10 ping on a local network. This makes playing together impossible when combined with gratuitous zombie, door, and vehicle desync.

[Dust]

try a dedicated server.
we are hosting zomboid servers since about 2 years some up to 30 players, never had any problems.

[hardy_conrad]

The desync issue is real, I've encountered in multiplayer before. However it's also possible to be overcome. Not sure how I can help as it sounds like you've already tried the obvious stuff.

[Cain]

i have been playing co op whit my my friends in the same room Xmas long week party... drunk galore .. and we keep having zombies in one screen that doesn't appear it the other players games
so yea
guess that mp was also its problems

[Father Lamb]

Lan is fine, had no issues like that. But if you're using a lot of mods? Good luck, that's when things get iffy.

[kit]

https://steamcommunity.com/app/108600/discussions/0/4780013756242986377?l
This seems relevant, this user is reporting critical memory leaks when playing and hosting on the same PC. Gonna try hosting on another computer that no one is playing on.

But this would mean everyone using the 'host' game feature is getting gamebreaking memory leaks?

[hardy_conrad]

Memory leaks, ah that brings back some nostalgia all right... Racking my brain mods might have been playing a role with our problems. Once we got rid of the clothing ones for example a lot of issues disappeared. Have a feeling Lamb is on to something, unless of course you aren't playing with mods.

[kit]

Yeah we've tried every single fix listed in the OP at the same time. Stripping the game down to its barest essentials with no room for mod, performance, or latency issues.

[hardy_conrad]

Ah sorry, I didn't see your mention of having removed all the mods. It's very odd as while lots of players will run into issues I don't think I've seen anyone have them as severe as you describe. At this point all I can do is wish you good luck I guess.

[kit]

Originally posted by hardy_conrad:

At this point all I can do is wish you good luck I guess.

I appreciate it! Been a pretty frustrating journey.

To the other users posting advice: Unfortunately I have tried everything you've described. :(
Gonna report back soon on whether hosting on a separate computer with no players addresses the issue.

[Father Lamb]

Originally posted by hardy_conrad:

Memory leaks, ah that brings back some nostalgia all right... Racking my brain mods might have been playing a role with our problems. Once we got rid of the clothing ones for example a lot of issues disappeared. Have a feeling Lamb is on to something, unless of course you aren't playing with mods.

I played Lan literally non-stop for hours without issue with just ONE other player, More than one might be an issue, and my own pc was the host as well, BUT.. 32gb of ram, and a 5900x at the time, so it was no issue, sync was perfect as well.

Some servers with more than 40 players are fine too, with TONS of mods, But the host is typically a PC with a threadripper and 128gb or more on the ram from what I've found out in some scenarios when I'd ask and snoop around.

So, if the server being hosted and some mods used do have a memory leak issue, there you have it.

[kit]

Extreme desync occurs without any lag, without any performance issues, and without any mods.

Running the dedicated server on a separate PC, virtual machine, or windows server client is a possible fix. In-game hosting is broken, so is running a dedicated server on the same PC as a connected game client.

EDIT: These fixes might help, but they do not solve the problem.

[Father Lamb]

Originally posted by kit:

Extreme desync occurs without any lag, without any performance issues, and without any mods.

Running the dedicated server on a separate PC, virtual machine, or windows server client is a possible fix. In-game hosting is broken, so is running a dedicated server on the same PC as a connected game client.

If its another whole pc needed... that points to it being hardware limited. in which this case... is why I've not experienced issue with a 7900x build and previously 5900x.. they're made for that stuff.

[kit]

Originally posted by Father Lamb:

Originally posted by kit:

Extreme desync occurs without any lag, without any performance issues, and without any mods.

Running the dedicated server on a separate PC, virtual machine, or windows server client is a possible fix. In-game hosting is broken, so is running a dedicated server on the same PC as a connected game client.

If its another whole pc needed... that points to it being hardware limited. in which this case... is why I've not experienced issue with a 7900x build and previously 5900x.. they're made for that stuff.

I've extensively tested this particular form of desync on multiple hardware platforms, including my current PC which (ironically) has a 5900x. This game is a single-threaded application btw, not sure how a 12-core CPU is "made for" it. Even my decade-old college laptop is more than capable of running PZ and hosting the server without serious performance issues.

If you want to replicate my testing I believe I've posted enough information here for you to do so. Try using the in-game hosting feature with another user connected over LAN, keep in mind the desync can take 30-60 minutes to manifest -- a big part of what makes it so frustrating to diagnose.

2 years ago this issue appeared on a completely different set of computers on a completely different wi-fi network, please understand that I'm not talking out of my ass when I say that it's not a latency, mod, or performance issue.

[Father Lamb]

Originally posted by kit:

Originally posted by Father Lamb:

If its another whole pc needed... that points to it being hardware limited. in which this case... is why I've not experienced issue with a 7900x build and previously 5900x.. they're made for that stuff.

I've extensively tested this particular form of desync on multiple hardware platforms, including my current PC which (ironically) has a 5900x. This game is a single-threaded application btw, not sure how a 12-core CPU is "made for" it. Even my decade-old college laptop is more than capable of running PZ and hosting the server without serious performance issues.

If you want to replicate my testing I believe I've posted enough information here for you to do so. Try using the in-game hosting feature with another user connected over LAN, keep in mind the desync can take 30-60 minutes to manifest -- a big part of what makes it so frustrating to diagnose.

2 years ago this issue appeared on a completely different set of computers on a completely different wi-fi network, please understand that I'm not talking out of my ass when I say that it's not a latency, mod, or performance issue.

Dude.. I didn't say the game was MADE FOR IT I said HOSTING with tons of MODS is where the 5900x came in handy. Your CPU handles the clients and mods heavily with this game.

DERP...

And as I said, I had ZERO issues for hours, days, a week straight playing this game on LAN with up to 3 people, 1 in home with me, and 2 others in the same city joining.

Nobody had issues with desync.

All I'm saying is, look into other things first. This game is picky, and when hosting, make sure proper ports are set right and nobody has conflicting settings, such as NAT and so on.

[kit]

Originally posted by Father Lamb:

DERP...

What method do you use for server hosting?