Modes

The default mode bundled within the modpack is quite aggressive. You may add/change modes by following the diff code blocks below. (+ for additions, ! for change, - for deletions). You may combine or partially add/change modes to achieve what you want.

Core

This mode has less mod incompatibilities.

Mod List

- Gnetum

Memory

This mode uses less memory at the cost of performance.

Java

For garbage collectors, Shenandoah generational mode (-XX:+UseShenandoahGC -XX:ShenandoahGCMode=generational) is generally recommended. Use G1GC (-XX:+UseG1GC) to save more, but with more frame stutters.

For arguments, you should always use CompactObjectHeaders (-XX:+UseCompactObjectHeaders), which is only available on Java 25+, and is the default on Java 27.

Config

Concurrent Chunk Management Engine

Change the snippet located in c2me.toml in the config folder:

[chunkSystem]
	# (Default: false) Whether to enable low memory mode
	# 
	# This option will attempt to aggressively unload unused chunks.
	# Only applies when useLegacyScheduling is disabled.
	# 
	lowMemoryMode = "true"

FerriteCore

Change the snippet located in ferritecore.mixin.properties in the config folder:

# Use a slightly more compact, but also slightly slower representation for block states
compactFastMap = true

ModernFix

Add these lines in modernfix-mixins.properties in the config folder:

mixin.perf.deduplicate_climate_parameters=true
mixin.perf.deduplicate_location=true

What does this do?

From the ModernFix wiki:

mixin.perf.deduplicate_climate_parameters: Deduplicates climate parameter objects used by the new biome system, can save ~2MB but also slows down datapack reload somewhat.

mixin.perf.deduplicate_location: All versions, but disabled by default due to load time impact. Deduplicates resource location namespaces and paths. This saves RAM but also increases the cost of constructing a new ResourceLocation by quite a bit.

Non-vanilla

This mode adds non-vanilla optimizations without significantly reducing parity.

Mod List

+ Footprint
+ Immersive Optimization
+ Let Me Despawn
+ TT20