I am running a modded minecraft server for forge 1.12.2 I have experience with running a server, but this baffles me. My tick rate is typically between 4-20 ms. I have allocated 4Gb of RAM so it has no memory problems with its 70% free space. And I have ran servers with more mods than this one. Somehow though, this is the laggiest server I had ever run, even when I have good wifi and everythign checks out. Any ideas as to why this is happening?
Depends what you mean by "lag". Test the mod pack in a local single player instance, preferably with a copy of the world map from the server. If you get the same lag, it's not the server, it's probably the world and/or the mod pack. That is a pretty light list of mods, so I kind of doubt that it's the pack, but something from a specific mod could be causing the issue.
If you're getting low fps then it's probably something in the world causing the issue like a bunch of entities laying around, for instance a bunch of drops from a mob farm that isn't working correctly.
If the world works fine in single player, then the issue is probably on the server, like if you get block lag, when you break a block and it takes a few seconds for it to pop then another few to be collected into your inventory. That's generally server sided because the server is overloaded with something, and again, that could be a large number of entities, or certain machines overflowing, etc. These types of things can be harder to find but a mod called lag goggles could help find what's causing the issue.
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