I was being plagued by constant disconnects when switching dimensions. Not anymore. I changed my Java arguments according to the SevTech Wiki and it works like a charm. Add these to your launcher before loading the game (only need to do this once). -Xmx8g -Xms8g -XX:+UseG1GC -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M -Dfml.readTimeout=120 Please do note, the first 2 lines will set your games memory to 8GB. This was recommended by the Modpack authors. The last line was recommended to me by SirWill because of the timeouts and disconnects. Together this made my game more stable. Try it and let me know if this helped for you as well!