We allow customers to select a preset of different options for their Minecraft server's command line options, all of which have been extensively tested over the years to ensure optimal performance on the various Minecraft versions they've worked best with. You can find the setting names and the relevant flags below.



Our minimal setting only sets the bare minimum:

  • Start/Max Allocated Memory (Xms/Xmx)
  • MetaSpace or PermGen sizes + minor MetaSpace tweaks
  • FML read timeout of 30 seconds

g1 / optimal

Our optimal setting is derived from Aikar's recommendations over at Sponge. For more information, please visit: https://forums.spongepowered.org/t/13239

  • Enables G1GC 
  • Enables UnlockExperimentalVMOptions 
  • Sets maximum GC pause time to 50ms
  • Sets TargetSurvivorRatio to 90
  • Sets G1MixedGCLiveThresholdPercent  to 50

For servers with 10GB of RAM or above:

  • Sets G1NewSizePercent  to 50
  • Sets G1MaxNewSizePercent to 80
  • Sets InitiatingHeapOccupancyPercent to 10


Our cms  setting enables 

  • Sets UseParNewGC 
  • Sets UseConcMarkSweepGC 
  • Enables CMSIncrementalPacing 
  • Sets CMSClassUnloadingEnabled 


Our auto setting changes between the minimal and optimal settings based on what server software the server is running. Currently, vanilla Minecraft will use to minimal while other server software like Paper and Forge will use optimal

Default .tweaks Section

You can find the default settings & warnings below.

## Java Garbage Collection Settings
# Possible values: cms, g1, optimal, minimal, auto
# Default: auto
# 'cms' enables -XX:+UseConcMarkSweepGC
# 'g1' enables -XX:+UseG1GC with max GC pause of 50ms
# 'minimal' sets only the memory and Metaspace/PermGen
# 'optimal' enables Aikar's recommended GC settings
# https://forums.spongepowered.org/t/13239
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