added some mods for fps.

recommended jvm parameters:-XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=32M -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:MaxTenuringThreshold=1 -XX:+AlwaysPreTouch -XX:+ParallelRefProcEnabled -XX:+PerfDisableSharedMem -XX:+UseStringDeduplication -XX:+TieredCompilation -XX:ReservedCodeCacheSize=512M -XX:+UseCodeCacheFlushing -XX:+SegmentedCodeCache -XX:ActiveProcessorCount=12 -XX:+UseNUMA -XX:+UseTypeSpeculation -XX:+OptimizeStringConcat -XX:+UseXMMForArrayCopy -Dsun.rti.allowSelfReference=true -Djava.net.preferIPv4Stack=true -Djna.nosys=true -Dlog4j2.formatMsgNoLookups=true -Dsun.io.useCanonPrefixCache=false -Djava.util.Arrays.useLegacyMergeSort=true -Dfile.encoding=UTF-8 -Dsun.java2d.opengl=true