-XX:+UseG1GC -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=25 -XX:G1ReservePercent=30 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=64M

hopefully it works lol



cpw's:
-XX:+UseG1GC -Xmx4G -Xms4G -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M

thread is old too, so it should work here
https://www.reddit.com/r/feedthebeast/comments/5jhuk9/modded_mc_and_memory_usage_a_history_with_a/