Extreme Lag Spikes on High-end PC

[Ryxas]

So, I recently spent roughly 10 hours building a 66 village "Iron Titan" on my survival world. I'm currently running forge 1.12. I won't bother listing the mods I have installed because I backed them up, removed them and ran the game with no change in my massive lag spikes. My computer is more than beefy enough to handle playing with ultra settings using a shader pack and keep a consistent 100fps. So ultimately my question boils down to what in forge is creating these massive lag spikes. For reference when I say massive I mean every 5-10 seconds my game almost freezes for 2 seconds and then goes back to normal. I will note that I have tried reducing all visual specs to the lowest settings without change. The only thing that I've done to my world that I can think would affect forge like this is that I have a portal set to spit an item out every 8 seconds give or take. This should keep the spawn chunks in my memory so that my 66 villages don't merge together and ruin my work. I thought that the redstone in the spawn chunks was the culprit until I looked at my debug and found that only 8% of my resources was going to tick. I've tested this issue in vanilla and in forge without mods. Vanilla runs perfectly normal (second image), where as Forge is stuttering my game (first image). Please help.

Edited July 3, 2017 by Ryxas

[Cloudy]

You have got WAY too much memory allocated. Sometimes allocating too much memory can cause issues too. 

 

Please try reducing it to a sensible amount (for instance 5gb) and see if is any better. 

 

Please also try it without optifine. 

[Ryxas]

2 minutes ago, Cloudy said:

Please try reducing it to a sensible amount (for instance 5gb) and see if is any better. 

 

I have tried it at 1, 4 and 8 GB as well. None of which affected this problem.

 

3 minutes ago, Cloudy said:

Please also try it without optifine. 

 

As stated in the post I have tried removing all mods, including optifine, and just running forge empty. The problem persists.

[Cloudy]

If you could provide the fml-client-latest.log with just forge on a session you are experiencing this issue on, we will be able to look into this further. 

[LuciusV]

I confirm this, the same happens for me without any mod

[Ravenleft]

This is a known (and fixed...workarounds provided below) issue related to how dimensions are handled. Forge unloads dimensions right away if there are no players present and apparently these Iron Titan farms relies on sending items to the nether, which is what's causing the lag spikes as the dimension is loaded when the item is sent then instantly unloaded because there are no players present...rinse and repeat over and over and over and over....

 

Workaround ingame: Simply put a chunkloader on the other side of the portal which will keep the dimension loaded all the time. (this obviously requires a mod that adds a chunkloader)

 

Permanent workaround:

 

Edit config\forge.cfg and look for this:

 

Quote

    # The time in ticks the server will wait when a dimension was queued to unload. This can be useful when rapidly loading and unloading dimensions, like e.g. throwing items through a nether portal a few time per second.
    I:dimensionUnloadQueueDelay=0

 

Change the 0 to something longer than the interval the items are sent at, 1 second = 20 ticks so with a 10 second cycle you'd want at least 200.

 

 

[Ryxas]

1 hour ago, Ravenleft said:

Edit config\forge.cfg and look for this:

 

Change the 0 to something longer than the interval the items are sent at, 1 second = 20 ticks so with a 10 second cycle you'd want at least 200.

 

You're my hero, it worked! Thank you so much.

[LexManos]

I'm still curious why the nether is even needed for this setup. The explanations I have heard is that it is a chunk loading mechanic for vanilla.... Because villages 'merge' if the chunks are unloaded.

But you're building it in spawn chunks which don't get unloaded. So i'm thinking this is unneeded even in vanilla. If anyone has documentation on the reasoning for this, i'd be interested in reading it.