diff --git a/src/pocketmine/MemoryManager.php b/src/pocketmine/MemoryManager.php
new file mode 100644
index 000000000..c60cbdfed
--- /dev/null
+++ b/src/pocketmine/MemoryManager.php
@@ -0,0 +1,159 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+namespace pocketmine;
+
+use pocketmine\event\server\LowMemoryEvent;
+use pocketmine\event\Timings;
+use pocketmine\scheduler\GarbageCollectionTask;
+use pocketmine\utils\Utils;
+
+class MemoryManager{
+
+	/** @var Server */
+	private $server;
+
+	private $memoryLimit;
+	private $globalMemoryLimit;
+	private $checkRate;
+	private $checkTicker = 0;
+	private $lowMemory = false;
+
+	private $continuousTrigger = true;
+	private $continuousTriggerRate;
+	private $continuousTriggerCount = 0;
+	private $continuousTriggerTicker = 0;
+
+	private $garbageCollectionPeriod;
+	private $garbageCollectionTicker = 0;
+	private $garbageCollectionTrigger;
+	private $garbageCollectionAsync;
+
+	private $chunkLimit;
+	private $chunkTrigger;
+
+	private $chunkCache;
+	private $cacheTrigger;
+
+	public function __construct(Server $server){
+		$this->server = $server;
+
+		$this->init();
+	}
+
+	private function init(){
+		$this->memoryLimit = ((int) $this->server->getProperty("memory.main-limit", 320)) * 1024 * 1024;
+		$this->globalMemoryLimit = ((int) $this->server->getProperty("memory.global-limit", 512)) * 1024 * 1024;
+		$this->checkRate = ((int) $this->server->getProperty("memory.check-rate", 20));
+		$this->continuousTrigger = (bool) $this->server->getProperty("memory.continuous-trigger", true);
+		$this->continuousTriggerRate = (int) $this->server->getProperty("memory.continuous-trigger-rate", 600);
+
+		$this->garbageCollectionPeriod = (int) $this->server->getProperty("memory.garbage-collection.period", 12000);
+		$this->garbageCollectionTrigger = (bool) $this->server->getProperty("memory.garbage-collection.low-memory-trigger", true);
+		$this->garbageCollectionAsync = (bool) $this->server->getProperty("memory.garbage-collection.collect-async-worker", true);
+
+		$this->chunkLimit = (int) $this->server->getProperty("memory.max-chunks.trigger-limit", 12000);
+		$this->chunkTrigger = (bool) $this->server->getProperty("memory.max-chunks.low-memory-trigger", true);
+
+		$this->chunkCache = (bool) $this->server->getProperty("memory.world-caches.disable-chunk-cache", true);
+		$this->cacheTrigger = (bool) $this->server->getProperty("memory.world-caches.low-memory-trigger", true);
+
+		gc_enable();
+	}
+
+	public function isLowMemory(){
+		return $this->lowMemory;
+	}
+
+	public function canUseChunkCache(){
+		return !($this->lowMemory and $this->chunkTrigger);
+	}
+
+	public function getViewDistance($distance){
+		return $this->lowMemory ? min($this->chunkLimit, $distance) : $distance;
+	}
+
+	public function trigger($memory, $limit, $global = false, $triggerCount = 0){
+		$this->server->getLogger()->debug("[Memory Manager] ".($global ? "Global " : "") ."Low memory triggered, limit ". round(($limit / 1024) / 1024, 2)."MB, using ". round(($memory / 1024) / 1024, 2)."MB");
+
+		if($this->cacheTrigger){
+			foreach($this->server->getLevels() as $level){
+				$level->clearCache(true);
+			}
+		}
+
+		$ev = new LowMemoryEvent($memory, $limit, $triggerCount);
+		$this->server->getPluginManager()->callEvent($ev);
+
+		if($this->garbageCollectionTrigger){
+			$this->triggerGarbageCollector();
+		}
+
+		$this->server->getLogger()->debug("[Memory Manager] Freed " . round(($ev->getMemoryFreed() / 1024) / 1024, 2)."MB");
+	}
+
+	public function check(){
+		if(($this->memoryLimit > 0 or $this->globalMemoryLimit > 0) and ++$this->checkTicker >= $this->checkRate){
+			$this->checkTicker = 0;
+			$memory = Utils::getMemoryUsage(true);
+			$trigger = false;
+			if($this->memoryLimit > 0 and $memory[0] > $this->memoryLimit){
+				$trigger = true;
+			}elseif($this->globalMemoryLimit > 0 and $memory[1] > $this->globalMemoryLimit){
+				$trigger = true;
+			}
+
+			if($trigger){
+				if($this->lowMemory and $this->continuousTrigger){
+					if(++$this->continuousTriggerTicker >= $this->continuousTriggerRate){
+						$this->continuousTriggerTicker = 0;
+						$this->trigger($memory, $this->memoryLimit, ++$this->continuousTriggerCount);
+					}
+				}else{
+					$this->lowMemory = true;
+					$this->continuousTriggerCount = 0;
+					$this->trigger($memory, $this->memoryLimit);
+				}
+			}else{
+				$this->lowMemory = false;
+			}
+		}
+
+		if($this->garbageCollectionPeriod > 0 and ++$this->garbageCollectionTicker >= $this->garbageCollectionPeriod){
+			$this->garbageCollectionTicker = 0;
+			$this->triggerGarbageCollector();
+		}
+	}
+
+	public function triggerGarbageCollector(){
+		Timings::$garbageCollectorTimer->startTiming();
+		gc_collect_cycles();
+
+		if($this->garbageCollectionAsync){
+			$size = $this->server->getScheduler()->getAsyncTaskPoolSize();
+			for($i = 0; $i < $size; ++$i){
+				$this->server->getScheduler()->scheduleAsyncTaskToWorker(new GarbageCollectionTask(), $i);
+			}
+		}
+
+		Timings::$garbageCollectorTimer->stopTiming();
+	}
+}
\ No newline at end of file
diff --git a/src/pocketmine/Player.php b/src/pocketmine/Player.php
index 951ab3c64..1be321b96 100644
--- a/src/pocketmine/Player.php
+++ b/src/pocketmine/Player.php
@@ -581,7 +581,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 		}
 	}
 
-	public function sendChunk($x, $z, $payload){
+	public function sendChunk($x, $z, &$payload){
 		if($this->connected === false){
 			return;
 		}
@@ -592,7 +592,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 		$pk = new FullChunkDataPacket();
 		$pk->chunkX = $x;
 		$pk->chunkZ = $z;
-		$pk->data = $payload;
+		$pk->data =& $payload;
 		$this->batchDataPacket($pk->setChannel(Network::CHANNEL_WORLD_CHUNKS));
 
 		if($this->spawned){
@@ -692,8 +692,8 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 
 		$this->nextChunkOrderRun = 200;
 
-		$radiusSquared = $this->viewDistance;
-		$radius = ceil(sqrt($radiusSquared));
+		$viewDistance = $this->server->getMemoryManager()->getViewDistance($this->viewDistance);
+		$radius = ceil(sqrt($viewDistance));
 		$side = ceil($radius / 2);
 
 		$newOrder = [];
@@ -716,7 +716,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 		asort($currentQueue);
 
 
-		$limit = $this->viewDistance;
+		$limit = $viewDistance;
 		foreach($currentQueue as $index => $distance){
 			if($limit-- <= 0){
 				break;
@@ -733,11 +733,12 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 
 		$loadedChunks = count($this->usedChunks);
 
-		if((count($newOrder) + $loadedChunks) > $this->viewDistance){
+
+		if((count($newOrder) + $loadedChunks) > $viewDistance){
 			$count = $loadedChunks;
 			$this->loadQueue = [];
 			foreach($newOrder as $k => $distance){
-				if(++$count > $this->viewDistance){
+				if(++$count > $viewDistance){
 					break;
 				}
 				$this->loadQueue[$k] = $distance;
@@ -1107,7 +1108,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 
 		$revert = false;
 
-		if($distanceSquared > 100){
+		if(($distanceSquared / $this->level->getTickRate()) > 100){
 			$revert = true;
 		}else{
 			if($this->chunk === null or !$this->chunk->isGenerated()){
@@ -2863,7 +2864,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 
 		if($source->isCancelled()){
 			return;
-		}elseif($this->getLastDamageCause() === $source){
+		}elseif($this->getLastDamageCause() === $source and $this->spawned){
 			$pk = new EntityEventPacket();
 			$pk->eid = $this->getId();
 			$pk->event = 2;
diff --git a/src/pocketmine/PocketMine.php b/src/pocketmine/PocketMine.php
index 14b3602ab..b6171a534 100644
--- a/src/pocketmine/PocketMine.php
+++ b/src/pocketmine/PocketMine.php
@@ -314,6 +314,24 @@ namespace pocketmine {
 		}
 	}
 
+	/**
+	 * @param object $value
+	 * @param bool   $includeCurrent
+	 *
+	 * @return int
+	 */
+	function getReferenceCount($value, $includeCurrent = true){
+		ob_start();
+		debug_zval_dump($value);
+		$ret = explode("\n", ob_get_contents());
+		ob_end_clean();
+
+		if(count($ret) >= 1 and preg_match('/^.* refcount\\(([0-9]+)\\)\\{$/', trim($ret[0]), $m) > 0){
+			return ((int) $m[1]) - ($includeCurrent ? 3 : 4); //$value + zval call + extra call
+		}
+		return -1;
+	}
+
 	function getTrace($start = 1, $trace = null){
 		if($trace === null){
 			if(function_exists("xdebug_get_function_stack")){
diff --git a/src/pocketmine/Server.php b/src/pocketmine/Server.php
index b50425e85..83b6f3a5f 100644
--- a/src/pocketmine/Server.php
+++ b/src/pocketmine/Server.php
@@ -159,6 +159,9 @@ class Server{
 	/** @var \AttachableThreadedLogger */
 	private $logger;
 
+	/** @var MemoryManager */
+	private $memoryManager;
+
 	/** @var CommandReader */
 	private $console = null;
 	private $consoleThreaded;
@@ -879,6 +882,13 @@ class Server{
 	 * @param Player $player
 	 */
 	public function removePlayer(Player $player){
+		if(isset($this->identifiers[$hash = spl_object_hash($player)])){
+			$identifier = $this->identifiers[$hash];
+			unset($this->players[$identifier]);
+			unset($this->identifiers[$hash]);
+			return;
+		}
+
 		foreach($this->players as $identifier => $p){
 			if($player === $p){
 				unset($this->players[$identifier]);
@@ -1521,9 +1531,20 @@ class Server{
 		$this->baseLang = new BaseLang($this->getProperty("settings.language", BaseLang::FALLBACK_LANGUAGE));
 		$this->logger->info($this->getLanguage()->translateString("language.selected", [$this->getLanguage()->getName(), $this->getLanguage()->getLang()]));
 
+		$this->memoryManager = new MemoryManager($this);
+
 		$this->logger->info($this->getLanguage()->translateString("pocketmine.server.start", [TextFormat::AQUA . $this->getVersion()]));
 
-		ServerScheduler::$WORKERS = $this->getProperty("settings.async-workers", ServerScheduler::$WORKERS);
+		if(($poolSize = $this->getProperty("settings.async-workers", "auto")) === "auto"){
+			$poolSize = ServerScheduler::$WORKERS;
+			$processors = Utils::getCoreCount();
+
+			if($processors > 0){
+				$poolSize = max(2, $processors);
+			}
+		}
+
+		ServerScheduler::$WORKERS = $poolSize;
 
 		if($this->getProperty("network.batch-threshold", 256) >= 0){
 			Network::$BATCH_THRESHOLD = (int) $this->getProperty("network.batch-threshold", 256);
@@ -1560,15 +1581,10 @@ class Server{
 		$this->maxPlayers = $this->getConfigInt("max-players", 20);
 		$this->setAutoSave($this->getConfigBoolean("auto-save", true));
 
-		if(($memory = str_replace("B", "", strtoupper($this->getConfigString("memory-limit", -1)))) !== false and $memory > 1){
-			$value = ["M" => 1, "G" => 1024];
-			$real = ((int) substr($memory, 0, -1)) * $value[substr($memory, -1)];
-			if($real < 128){
-				$this->logger->warning($this->getName() . " may not work right with less than 128MB of memory");
-			}
-			@ini_set("memory_limit", $memory);
-			$this->logger->notice("The memory limit will only affect the main thread, and it's unreliable.");
-			$this->logger->notice("To control the memory usage, reduce the amount of threads and chunks loaded");
+		if($this->getConfigString("memory-limit", -1) !== false){
+			$this->logger->notice("The memory-limit setting has been deprecated.");
+			$this->logger->notice("There are new memory settings on pocketmine.yml to tune memory and events.");
+			$this->logger->notice("You can also reduce the amount of threads and chunks loaded control the memory usage.");
 		}
 
 		if($this->getConfigBoolean("hardcore", false) === true and $this->getDifficulty() < 3){
@@ -1791,11 +1807,7 @@ class Server{
 		}
 
 		if(!$forceSync and $this->networkCompressionAsync){
-			$task = new CompressBatchedTask();
-			$task->targets = $targets;
-			$task->data = $str;
-			$task->channel = $channel;
-			$task->level = $this->networkCompressionLevel;
+			$task = new CompressBatchedTask($str, $targets, $this->networkCompressionLevel, $channel);
 			$this->getScheduler()->scheduleAsyncTask($task);
 		}else{
 			$this->broadcastPacketsCallback(zlib_encode($str, ZLIB_ENCODING_DEFLATE, $this->networkCompressionLevel), $targets, $channel);
@@ -1904,17 +1916,6 @@ class Server{
 		$this->properties->reload();
 		$this->maxPlayers = $this->getConfigInt("max-players", 20);
 
-		if(($memory = str_replace("B", "", strtoupper($this->getConfigString("memory-limit", -1)))) !== false and $memory > 1){
-			$value = ["M" => 1, "G" => 1024];
-			$real = ((int) substr($memory, 0, -1)) * $value[substr($memory, -1)];
-			if($real < 256){
-				$this->logger->warning($this->getName() . " may not work right with less than 256MB of memory", true, true, 0);
-			}
-			@ini_set("memory_limit", $memory);
-			$this->logger->notice("The memory limit will only affect the main thread, and it's unreliable.");
-			$this->logger->notice("To control the memory usage, reduce the amount of threads and chunks loaded");
-		}
-
 		if($this->getConfigBoolean("hardcore", false) === true and $this->getDifficulty() < 3){
 			$this->setConfigInt("difficulty", 3);
 		}
@@ -2211,8 +2212,7 @@ class Server{
 				if($player->isOnline()){
 					$player->save();
 				}elseif(!$player->isConnected()){
-					unset($this->players[$index]);
-					unset($this->identifiers[spl_object_hash($player)]);
+					$this->removePlayer($player);
 				}
 			}
 
@@ -2248,8 +2248,8 @@ class Server{
 			"port" => $this->getPort(),
 			"os" => Utils::getOS(),
 			"name" => $this->getName(),
-			"memory_total" => $this->getConfigString("memory-limit"),
-			"memory_usage" => $this->getMemoryUsage(),
+			"memory_total" => $this->getConfigString("memory-limit"), //TODO
+			"memory_usage" => Utils::getMemoryUsage(),
 			"php_version" => PHP_VERSION,
 			"version" => $version->get(true),
 			"build" => $version->getBuild(),
@@ -2285,13 +2285,20 @@ class Server{
 		return $this->network;
 	}
 
+	/**
+	 * @return MemoryManager
+	 */
+	public function getMemoryManager(){
+		return $this->memoryManager;
+	}
+
 	private function titleTick(){
 		if(!Terminal::hasFormattingCodes()){
 			return;
 		}
 		
-		$u = $this->getMemoryUsage(true);
-		$usage = round(($u[0] / 1024) / 1024, 2) . "/".round(($u[1] / 1024) / 1024, 2)." MB @ " . $this->getThreadCount() . " threads";
+		$u = Utils::getMemoryUsage(true);
+		$usage = round(($u[0] / 1024) / 1024, 2) . "/" . round(($u[1] / 1024) / 1024, 2) . "/".round(($u[2] / 1024) / 1024, 2)." MB @ " . Utils::getThreadCount() . " threads";
 
 		echo "\x1b]0;" . $this->getName() . " " .
 			$this->getPocketMineVersion() .
@@ -2304,47 +2311,6 @@ class Server{
 
 		$this->network->resetStatistics();
 	}
-	
-	public function getMemoryUsage($advanced = false){
-		$VmSize = null;
-		$VmRSS = null;
-		if(Utils::getOS() === "linux" or Utils::getOS() === "bsd"){
-			$status = file_get_contents("/proc/self/status");
-			if(preg_match("/VmRSS:[ \t]+([0-9]+) kB/", $status, $matches) > 0){
-				$VmRSS = $matches[1] * 1024;
-			}
-
-			if(preg_match("/VmSize:[ \t]+([0-9]+) kB/", $status, $matches) > 0){
-				$VmSize = $matches[1] * 1024;
-			}
-		}
-
-		if($VmRSS === null){
-			$VmRSS = memory_get_usage();
-		}
-
-		if(!$advanced){
-			return $VmRSS;
-		}
-
-		if($VmSize === null){
-			$VmSize = memory_get_usage(true);
-		}
-
-		return [$VmRSS, $VmSize];
-	}
-	
-	public function getThreadCount(){
-		if(Utils::getOS() === "linux" or Utils::getOS() === "bsd"){
-			
-			if(preg_match("/Threads:[ \t]+([0-9]+)/", file_get_contents("/proc/self/status"), $matches) > 0){
-				return (int) $matches[1];
-			}
-		}
-		
-		return count(ThreadManager::getInstance()->getAll()) + 3; //RakLib + MainLogger + Main Thread
-	}
-
 
 	/**
 	 * @param string $address
@@ -2365,7 +2331,7 @@ class Server{
 				}
 			}
 
-			$this->blockAddress($address, 600);
+			$this->getNetwork()->blockAddress($address, 600);
 		}
 		//TODO: add raw packet events
 	}
@@ -2398,7 +2364,7 @@ class Server{
 
 		if(($this->tickCounter & 0b1111) === 0){
 			$this->titleTick();
-			if(isset($this->queryHandler) and ($this->tickCounter & 0b111111111) === 0){
+			if($this->queryHandler !== null and ($this->tickCounter & 0b111111111) === 0){
 				try{
 					$this->queryHandler->regenerateInfo();
 				}catch(\Exception $e){
@@ -2415,6 +2381,7 @@ class Server{
 			}
 		}
 
+		$this->getMemoryManager()->check();
 
 		Timings::$serverTickTimer->stopTiming();
 
diff --git a/src/pocketmine/block/Flowable.php b/src/pocketmine/block/Flowable.php
index ccdb725e5..1072234a8 100644
--- a/src/pocketmine/block/Flowable.php
+++ b/src/pocketmine/block/Flowable.php
@@ -22,12 +22,18 @@
 namespace pocketmine\block;
 
 
+use pocketmine\item\Item;
+
 abstract class Flowable extends Transparent{
 
 	public function canBeFlowedInto(){
 		return true;
 	}
 
+	public function getBreakTime(Item $item){
+		return 0;
+	}
+
 	public function isSolid(){
 		return false;
 	}
diff --git a/src/pocketmine/command/CommandReader.php b/src/pocketmine/command/CommandReader.php
index 9695d438c..a2783c15a 100644
--- a/src/pocketmine/command/CommandReader.php
+++ b/src/pocketmine/command/CommandReader.php
@@ -78,7 +78,7 @@ class CommandReader extends Thread{
 			if(($line = $this->readLine()) !== ""){
 				$this->buffer->synchronized(function (\Threaded $buffer, $line){
 					$buffer[] = preg_replace("#\\x1b\\x5b([^\\x1b]*\\x7e|[\\x40-\\x50])#", "", $line);
-				}, $this->buffer, $line );
+				}, $this->buffer, $line);
 			}elseif((microtime(true) - $lastLine) <= 0.1){ //Non blocking! Sleep to save CPU
 				usleep(40000);
 			}
diff --git a/src/pocketmine/command/defaults/BanListCommand.php b/src/pocketmine/command/defaults/BanListCommand.php
index 8d1d75340..251a096d3 100644
--- a/src/pocketmine/command/defaults/BanListCommand.php
+++ b/src/pocketmine/command/defaults/BanListCommand.php
@@ -52,6 +52,9 @@ class BanListCommand extends VanillaCommand{
 
 				return false;
 			}
+		}else{
+			$list = $sender->getServer()->getNameBans();
+			$args[0] = "players";
 		}
 
 		$message = "";
diff --git a/src/pocketmine/command/defaults/StatusCommand.php b/src/pocketmine/command/defaults/StatusCommand.php
index 544eef036..4851f06f3 100644
--- a/src/pocketmine/command/defaults/StatusCommand.php
+++ b/src/pocketmine/command/defaults/StatusCommand.php
@@ -23,6 +23,7 @@ namespace pocketmine\command\defaults;
 
 use pocketmine\command\CommandSender;
 use pocketmine\utils\TextFormat;
+use pocketmine\utils\Utils;
 
 class StatusCommand extends VanillaCommand{
 
@@ -40,14 +41,16 @@ class StatusCommand extends VanillaCommand{
 			return true;
 		}
 
+		$mUsage = Utils::getMemoryUsage(true);
+
 		$server = $sender->getServer();
 		$sender->sendMessage(TextFormat::GREEN . "---- " . TextFormat::WHITE . "Server status" . TextFormat::GREEN . " ----");
 		$sender->sendMessage(TextFormat::GOLD . "TPS: " . TextFormat::WHITE . $server->getTicksPerSecond());
 		$sender->sendMessage(TextFormat::GOLD . "TPS Load: " . TextFormat::WHITE . $server->getTickUsage() . "%");
 		$sender->sendMessage(TextFormat::GOLD . "Upload: " . TextFormat::WHITE . round($server->getNetwork()->getUpload() / 1024, 2) . " kB/s");
 		$sender->sendMessage(TextFormat::GOLD . "Download: " . TextFormat::WHITE . round($server->getNetwork()->getDownload() / 1024, 2) . " kB/s");
-		$sender->sendMessage(TextFormat::GOLD . "Memory: " . TextFormat::WHITE . round(($server->getMemoryUsage() / 1024) / 1024, 2) . " MB");
-		$sender->sendMessage(TextFormat::GOLD . "Threads: " . TextFormat::WHITE . $server->getThreadCount());		
+		$sender->sendMessage(TextFormat::GOLD . "Memory: " . TextFormat::WHITE . round(($mUsage[0] / 1024) / 1024, 2) . "/".round(($mUsage[1] / 1024) / 1024, 2) . "/".round(($mUsage[2] / 1024) / 1024, 2) . " MB");
+		$sender->sendMessage(TextFormat::GOLD . "Threads: " . TextFormat::WHITE . Utils::getThreadCount());
 
 		return true;
 	}
diff --git a/src/pocketmine/entity/Squid.php b/src/pocketmine/entity/Squid.php
index 31fbc48ec..653058426 100644
--- a/src/pocketmine/entity/Squid.php
+++ b/src/pocketmine/entity/Squid.php
@@ -43,6 +43,8 @@ class Squid extends WaterAnimal implements Ageable{
 	public $swimDirection = null;
 	public $swimSpeed = 0.1;
 
+	private $switchDirectionTicker = 0;
+
 	public function initEntity(){
 		$this->setMaxHealth(5);
 		parent::initEntity();
@@ -80,8 +82,11 @@ class Squid extends WaterAnimal implements Ageable{
 			return false;
 		}
 
-		if($currentTick % 20 === 0 and mt_rand(0, 100) < 5){
-			$this->swimDirection = null;
+		if(++$this->switchDirectionTicker === 100){
+			$this->switchDirectionTicker = 0;
+			if(mt_rand(0, 100) < 50){
+				$this->swimDirection = null;
+			}
 		}
 
 		$this->lastUpdate = $currentTick;
diff --git a/src/pocketmine/event/Timings.php b/src/pocketmine/event/Timings.php
index 3c78e3dca..171f335ea 100644
--- a/src/pocketmine/event/Timings.php
+++ b/src/pocketmine/event/Timings.php
@@ -33,6 +33,8 @@ abstract class Timings{
 	/** @var TimingsHandler */
 	public static $serverTickTimer;
 	/** @var TimingsHandler */
+	public static $garbageCollectorTimer;
+	/** @var TimingsHandler */
 	public static $playerListTimer;
 	/** @var TimingsHandler */
 	public static $connectionTimer;
@@ -96,6 +98,7 @@ abstract class Timings{
 		}
 
 		self::$serverTickTimer = new TimingsHandler("** Full Server Tick");
+		self::$garbageCollectorTimer = new TimingsHandler("Garbage Collector");
 		self::$playerListTimer = new TimingsHandler("Player List");
 		self::$connectionTimer = new TimingsHandler("Connection Handler");
 		self::$tickablesTimer = new TimingsHandler("Tickables");
diff --git a/src/pocketmine/event/server/LowMemoryEvent.php b/src/pocketmine/event/server/LowMemoryEvent.php
new file mode 100644
index 000000000..41d0d499e
--- /dev/null
+++ b/src/pocketmine/event/server/LowMemoryEvent.php
@@ -0,0 +1,79 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link   http://www.pocketmine.net/
+ *
+ *
+ */
+
+namespace pocketmine\event\server;
+use pocketmine\utils\Utils;
+
+
+/**
+ * Called when the server is in a low-memory state as defined by the properties
+ * Plugins should free caches or other non-essential data.
+ */
+class LowMemoryEvent extends ServerEvent{
+	public static $handlerList = null;
+
+	private $memory;
+	private $memoryLimit;
+	private $triggerCount;
+
+	public function __construct($memory, $memoryLimit, $triggerCount = 0){
+		$this->memory = $memory;
+		$this->memoryLimit = $memoryLimit;
+		$this->triggerCount = (int) $triggerCount;
+	}
+
+	/**
+	 * Returns the memory usage at the time of the event call (in bytes)
+	 *
+	 * @return int
+	 */
+	public function getMemory(){
+		return $this->memory;
+	}
+
+	/**
+	 * Returns the memory limit defined (in bytes)
+	 *
+	 * @return int
+	 */
+	public function getMemoryLimit(){
+		return $this->memory;
+	}
+
+	/**
+	 * Returns the times this event has been called in the current low-memory state
+	 *
+	 * @return int
+	 */
+	public function getTriggerCount(){
+		return $this->triggerCount;
+	}
+
+	/**
+	 * Amount of memory already freed
+	 *
+	 * @return int
+	 */
+	public function getMemoryFreed(){
+		return $this->getMemory() - Utils::getMemoryUsage();
+	}
+
+}
\ No newline at end of file
diff --git a/src/pocketmine/level/Level.php b/src/pocketmine/level/Level.php
index 4410303fd..acab46959 100644
--- a/src/pocketmine/level/Level.php
+++ b/src/pocketmine/level/Level.php
@@ -93,12 +93,10 @@ use pocketmine\scheduler\AsyncTask;
 use pocketmine\Server;
 use pocketmine\tile\Chest;
 use pocketmine\tile\Tile;
-use pocketmine\utils\Cache;
 use pocketmine\utils\LevelException;
 use pocketmine\utils\MainLogger;
 use pocketmine\utils\Random;
 use pocketmine\utils\ReversePriorityQueue;
-use pocketmine\utils\TextFormat;
 use pocketmine\level\particle\Particle;
 use pocketmine\level\sound\Sound;
 use pocketmine\entity\Effect;
@@ -145,6 +143,8 @@ class Level implements ChunkManager, Metadatable{
 
 	private $cacheChunks = false;
 
+	private $sendTimeTicker = 0;
+
 	/** @var Server */
 	private $server;
 
@@ -512,6 +512,7 @@ class Level implements ChunkManager, Metadatable{
 	 */
 	public function freeChunk($X, $Z, Player $player){
 		unset($this->usedChunks[$index = Level::chunkHash($X, $Z)][$player->getId()]);
+
 		$this->unloadChunkRequest($X, $Z, true);
 	}
 
@@ -553,8 +554,9 @@ class Level implements ChunkManager, Metadatable{
 
 		$this->checkTime();
 
-		if(($currentTick % 200) === 0){
+		if(++$this->sendTimeTicker === 200){
 			$this->sendTime();
+			$this->sendTimeTicker = 0;
 		}
 
 		$this->unloadChunks();
@@ -646,7 +648,11 @@ class Level implements ChunkManager, Metadatable{
 		Server::broadcastPacket($target, $pk->setChannel(Network::CHANNEL_BLOCKS));
 	}
 
-	public function clearCache(){
+	public function clearCache($full = false){
+		if($full){
+			$this->chunkCache = [];
+		}
+
 		$this->blockCache = [];
 	}
 
@@ -1987,11 +1993,11 @@ class Level implements ChunkManager, Metadatable{
 		}
 	}
 
-	public function chunkRequestCallback($x, $z, $payload){
+	public function chunkRequestCallback($x, $z, &$payload){
 		$index = Level::chunkHash($x, $z);
 
-		if(!isset($this->chunkCache[$index]) and $this->cacheChunks){
-			$this->chunkCache[$index] = $payload;
+		if(!isset($this->chunkCache[$index]) and $this->cacheChunks and $this->server->getMemoryManager()->canUseChunkCache()){
+			$this->chunkCache[$index] =& $payload;
 		}
 
 		if(isset($this->chunkSendTasks[$index])){
@@ -2077,7 +2083,7 @@ class Level implements ChunkManager, Metadatable{
 	 * @return bool
 	 */
 	public function isChunkInUse($x, $z){
-		return isset($this->usedChunks[Level::chunkHash($x, $z)]) and count($this->usedChunks[Level::chunkHash($x, $z)]) > 0;
+		return isset($this->usedChunks[$index = Level::chunkHash($x, $z)]) and count($this->usedChunks[$index]) > 0;
 	}
 
 	/**
@@ -2118,6 +2124,8 @@ class Level implements ChunkManager, Metadatable{
 			return false;
 		}
 
+		$chunk->setChanged(false);
+
 		return true;
 	}
 
@@ -2145,6 +2153,10 @@ class Level implements ChunkManager, Metadatable{
 			return false;
 		}
 
+		if(!$this->isChunkLoaded($x, $z)){
+			return true;
+		}
+
 		$this->timings->doChunkUnload->startTiming();
 
 		$index = Level::chunkHash($x, $z);
@@ -2154,6 +2166,7 @@ class Level implements ChunkManager, Metadatable{
 		if($chunk !== null and $chunk->getProvider() !== null){
 			$this->server->getPluginManager()->callEvent($ev = new ChunkUnloadEvent($chunk));
 			if($ev->isCancelled()){
+				$this->timings->doChunkUnload->stopTiming();
 				return false;
 			}
 		}
@@ -2187,6 +2200,10 @@ class Level implements ChunkManager, Metadatable{
 		unset($this->chunkTickList[$index]);
 		unset($this->chunkCache[$index]);
 
+		$refs = \pocketmine\getReferenceCount($chunk);
+
+		//$this->server->getLogger()->debug("Unloaded $x $z (".count($this->getChunks()).") [refs $refs]");
+
 		$this->timings->doChunkUnload->stopTiming();
 
 		return true;
diff --git a/src/pocketmine/level/format/FullChunk.php b/src/pocketmine/level/format/FullChunk.php
index 548d8235e..38faba525 100644
--- a/src/pocketmine/level/format/FullChunk.php
+++ b/src/pocketmine/level/format/FullChunk.php
@@ -288,25 +288,25 @@ interface FullChunk{
 	/**
 	 * @return string[]
 	 */
-	public function getBiomeIdArray();
+	public function &getBiomeIdArray();
 
 	/**
 	 * @return int[]
 	 */
-	public function getBiomeColorArray();
+	public function &getBiomeColorArray();
 
 	/**
 	 * @return int[]
 	 */
-	public function getHeightMapArray();
+	public function &getHeightMapArray();
 
-	public function getBlockIdArray();
+	public function &getBlockIdArray();
 
-	public function getBlockDataArray();
+	public function &getBlockDataArray();
 
-	public function getBlockSkyLightArray();
+	public function &getBlockSkyLightArray();
 
-	public function getBlockLightArray();
+	public function &getBlockLightArray();
 
 	public function toBinary();
 
@@ -328,7 +328,7 @@ interface FullChunk{
 	 *
 	 * @return FullChunk
 	 */
-	public static function fromBinary($data, LevelProvider $provider = null);
+	public static function fromBinary(&$data, LevelProvider $provider = null);
 
 	/**
 	 * @param string        $data
@@ -336,6 +336,6 @@ interface FullChunk{
 	 *
 	 * @return FullChunk
 	 */
-	public static function fromFastBinary($data, LevelProvider $provider = null);
+	public static function fromFastBinary(&$data, LevelProvider $provider = null);
 
 }
\ No newline at end of file
diff --git a/src/pocketmine/level/format/generic/BaseFullChunk.php b/src/pocketmine/level/format/generic/BaseFullChunk.php
index 1a1ff95ee..6e46a83ce 100644
--- a/src/pocketmine/level/format/generic/BaseFullChunk.php
+++ b/src/pocketmine/level/format/generic/BaseFullChunk.php
@@ -87,13 +87,13 @@ abstract class BaseFullChunk implements FullChunk{
 		$this->x = (int) $x;
 		$this->z = (int) $z;
 
-		$this->blocks = $blocks;
-		$this->data = $data;
-		$this->skyLight = $skyLight;
-		$this->blockLight = $blockLight;
+		$this->blocks =& $blocks;
+		$this->data =& $data;
+		$this->skyLight =& $skyLight;
+		$this->blockLight =& $blockLight;
 
 		if(strlen($biomeIds) === 256){
-			$this->biomeIds = $biomeIds;
+			$this->biomeIds =& $biomeIds;
 		}else{
 			$this->biomeIds = str_repeat("\x01", 256);
 		}
@@ -321,31 +321,31 @@ abstract class BaseFullChunk implements FullChunk{
 		return true;
 	}
 
-	public function getBlockIdArray(){
+	public function &getBlockIdArray(){
 		return $this->blocks;
 	}
 
-	public function getBlockDataArray(){
+	public function &getBlockDataArray(){
 		return $this->data;
 	}
 
-	public function getBlockSkyLightArray(){
+	public function &getBlockSkyLightArray(){
 		return $this->skyLight;
 	}
 
-	public function getBlockLightArray(){
+	public function &getBlockLightArray(){
 		return $this->blockLight;
 	}
 
-	public function getBiomeIdArray(){
+	public function &getBiomeIdArray(){
 		return $this->biomeIds;
 	}
 
-	public function getBiomeColorArray(){
+	public function &getBiomeColorArray(){
 		return $this->biomeColors;
 	}
 
-	public function getHeightMapArray(){
+	public function &getHeightMapArray(){
 		return $this->heightMap;
 	}
 
@@ -357,11 +357,11 @@ abstract class BaseFullChunk implements FullChunk{
 		$this->hasChanged = (bool) $changed;
 	}
 
-	public static function fromFastBinary($data, LevelProvider $provider = null){
+	public static function &fromFastBinary(&$data, LevelProvider $provider = null){
 		static::fromBinary($data, $provider);
 	}
 
-	public function toFastBinary(){
+	public function &toFastBinary(){
 		return $this->toBinary();
 	}
 
diff --git a/src/pocketmine/level/format/leveldb/Chunk.php b/src/pocketmine/level/format/leveldb/Chunk.php
index be853c73b..40d7fe93b 100644
--- a/src/pocketmine/level/format/leveldb/Chunk.php
+++ b/src/pocketmine/level/format/leveldb/Chunk.php
@@ -221,7 +221,7 @@ class Chunk extends BaseFullChunk{
 		$this->isGenerated = (bool) $value;
 	}
 
-	public static function fromFastBinary($data, LevelProvider $provider = null){
+	public static function fromFastBinary(&$data, LevelProvider $provider = null){
 		return self::fromBinary($data, $provider);
 	}
 
@@ -231,7 +231,7 @@ class Chunk extends BaseFullChunk{
 	 *
 	 * @return Chunk
 	 */
-	public static function fromBinary($data, LevelProvider $provider = null){
+	public static function fromBinary(&$data, LevelProvider $provider = null){
 		try{
 			$chunkX = Binary::readLInt(substr($data, 0, 4));
 			$chunkZ = Binary::readLInt(substr($data, 4, 4));
diff --git a/src/pocketmine/level/format/mcregion/Chunk.php b/src/pocketmine/level/format/mcregion/Chunk.php
index 0c9947140..2b83aee7c 100644
--- a/src/pocketmine/level/format/mcregion/Chunk.php
+++ b/src/pocketmine/level/format/mcregion/Chunk.php
@@ -276,7 +276,7 @@ class Chunk extends BaseFullChunk{
 	 *
 	 * @return Chunk
 	 */
-	public static function fromBinary($data, LevelProvider $provider = null){
+	public static function fromBinary(&$data, LevelProvider $provider = null){
 		$nbt = new NBT(NBT::BIG_ENDIAN);
 
 		try{
@@ -293,7 +293,7 @@ class Chunk extends BaseFullChunk{
 		}
 	}
 	
-	public static function fromFastBinary($data, LevelProvider $provider = null){
+	public static function fromFastBinary(&$data, LevelProvider $provider = null){
 
 		try{
 			$offset = 0;
@@ -340,11 +340,11 @@ class Chunk extends BaseFullChunk{
 		}
 	}
 	
-	public function toFastBinary(){
+	public function &toFastBinary(){
 		$biomeColors = pack("N*", ...$this->getBiomeColorArray());
 		$heightMap = pack("N*", ...$this->getHeightMapArray());
 
-		return
+		$data =
 			Binary::writeInt($this->x) .
 			Binary::writeInt($this->z) .
 			$this->getBlockIdArray() .
@@ -355,9 +355,10 @@ class Chunk extends BaseFullChunk{
 			$biomeColors .
 			$heightMap .
 			chr(($this->isPopulated() ? 1 << 1 : 0) + ($this->isGenerated() ? 1 : 0));
+		return $data;
 	}
 
-	public function toBinary(){
+	public function &toBinary(){
 		$nbt = clone $this->getNBT();
 
 		$nbt->xPos = new Int("xPos", $this->x);
@@ -400,7 +401,8 @@ class Chunk extends BaseFullChunk{
 		$nbt->setName("Level");
 		$writer->setData(new Compound("", ["Level" => $nbt]));
 
-		return $writer->writeCompressed(ZLIB_ENCODING_DEFLATE, RegionLoader::$COMPRESSION_LEVEL);
+		$data =& $writer->writeCompressed(ZLIB_ENCODING_DEFLATE, RegionLoader::$COMPRESSION_LEVEL);
+		return $data;
 	}
 
 	/**
diff --git a/src/pocketmine/level/format/mcregion/RegionLoader.php b/src/pocketmine/level/format/mcregion/RegionLoader.php
index 7d5955290..1bc30e918 100644
--- a/src/pocketmine/level/format/mcregion/RegionLoader.php
+++ b/src/pocketmine/level/format/mcregion/RegionLoader.php
@@ -130,7 +130,8 @@ class RegionLoader{
 			return null;
 		}
 
-		$chunk = Chunk::fromBinary(fread($this->filePointer, $length - 1), $this->levelProvider);
+		$data = fread($this->filePointer, $length - 1);
+		$chunk = Chunk::fromBinary($data, $this->levelProvider);
 		if($chunk instanceof Chunk){
 			return $chunk;
 		}elseif($forward === false){
@@ -156,12 +157,15 @@ class RegionLoader{
 		$nbt->TerrainPopulated = new Byte("TerrainPopulated", 0);
 		$nbt->V = new Byte("V", self::VERSION);
 		$nbt->InhabitedTime = new Long("InhabitedTime", 0);
-		$nbt->Biomes = new ByteArray("Biomes", str_repeat(Binary::writeByte(-1), 256));
+		$biomes = str_repeat(Binary::writeByte(-1), 256);
+		$nbt->Biomes = new ByteArray("Biomes", $biomes);
 		$nbt->HeightMap = new IntArray("HeightMap", array_fill(0, 256, 127));
 		$nbt->BiomeColors = new IntArray("BiomeColors", array_fill(0, 256, Binary::readInt("\x00\x85\xb2\x4a")));
 
-		$nbt->Blocks = new ByteArray("Blocks", str_repeat("\x00", 32768));
-		$nbt->Data = new ByteArray("Data", $half = str_repeat("\x00", 16384));
+		$half = str_repeat("\x00", 16384);
+		$full = $half . $half;
+		$nbt->Blocks = new ByteArray("Blocks", $full);
+		$nbt->Data = new ByteArray("Data", $half);
 		$nbt->SkyLight = new ByteArray("SkyLight", $half);
 		$nbt->BlockLight = new ByteArray("BlockLight", $half);
 
@@ -181,7 +185,7 @@ class RegionLoader{
 		}
 	}
 
-	protected function saveChunk($x, $z, $chunkData){
+	protected function saveChunk($x, $z, &$chunkData){
 		$length = strlen($chunkData) + 1;
 		if($length + 4 > self::MAX_SECTOR_LENGTH){
 			throw new ChunkException("Chunk is too big! ".($length + 4)." > ".self::MAX_SECTOR_LENGTH);
@@ -208,7 +212,7 @@ class RegionLoader{
 
 	public function writeChunk(FullChunk $chunk){
 		$this->lastUsed = time();
-		$chunkData = $chunk->toBinary();
+		$chunkData = &$chunk->toBinary();
 		if($chunkData !== false){
 			$this->saveChunk($chunk->getX() - ($this->getX() * 32), $chunk->getZ() - ($this->getZ() * 32), $chunkData);
 		}
diff --git a/src/pocketmine/nbt/NBT.php b/src/pocketmine/nbt/NBT.php
index c493e63c4..a287f36b4 100644
--- a/src/pocketmine/nbt/NBT.php
+++ b/src/pocketmine/nbt/NBT.php
@@ -84,7 +84,7 @@ class NBT{
 		return $len === 1 ? $this->buffer{$this->offset++} : substr($this->buffer, ($this->offset += $len) - $len, $len);
 	}
 
-	public function put($v){
+	public function put(&$v){
 		$this->buffer .= $v;
 	}
 
@@ -99,7 +99,7 @@ class NBT{
 
 	public function read($buffer, $doMultiple = false){
 		$this->offset = 0;
-		$this->buffer = $buffer;
+		$this->buffer =& $buffer;
 		$this->data = $this->readTag();
 		if($doMultiple and $this->offset < strlen($this->buffer)){
 			$this->data = [$this->data];
@@ -117,28 +117,30 @@ class NBT{
 	/**
 	 * @return string|bool
 	 */
-	public function write(){
+	public function &write(){
 		$this->offset = 0;
+		$data = false;
 		if($this->data instanceof Compound){
 			$this->writeTag($this->data);
 
-			return $this->buffer;
+			$data =& $this->buffer;
 		}elseif(is_array($this->data)){
 			foreach($this->data as $tag){
 				$this->writeTag($tag);
 			}
-			return $this->buffer;
+			$data =& $this->buffer;
 		}
 
-		return false;
+		return $data;
 	}
 
-	public function writeCompressed($compression = ZLIB_ENCODING_GZIP, $level = 7){
+	public function &writeCompressed($compression = ZLIB_ENCODING_GZIP, $level = 7){
+		$data = false;
 		if(($write = $this->write()) !== false){
-			return zlib_encode($write, $compression, $level);
+			$data = zlib_encode($write, $compression, $level);
 		}
 
-		return false;
+		return $data;
 	}
 
 	public function readTag(){
@@ -256,7 +258,7 @@ class NBT{
 		return $this->get($this->getShort());
 	}
 
-	public function putString($v){
+	public function putString(&$v){
 		$this->putShort(strlen($v));
 		$this->buffer .= $v;
 	}
diff --git a/src/pocketmine/nbt/tag/ByteArray.php b/src/pocketmine/nbt/tag/ByteArray.php
index 5f80e1452..f83f4b735 100644
--- a/src/pocketmine/nbt/tag/ByteArray.php
+++ b/src/pocketmine/nbt/tag/ByteArray.php
@@ -27,6 +27,13 @@ use pocketmine\nbt\NBT;
 
 class ByteArray extends NamedTag{
 
+	public function __construct($name = "", &$value = null){
+		$this->name = $name;
+		if($value !== null){
+			$this->value =& $value;
+		}
+	}
+
 	public function getType(){
 		return NBT::TAG_ByteArray;
 	}
diff --git a/src/pocketmine/nbt/tag/IntArray.php b/src/pocketmine/nbt/tag/IntArray.php
index c1500fa23..3bcdabbe9 100644
--- a/src/pocketmine/nbt/tag/IntArray.php
+++ b/src/pocketmine/nbt/tag/IntArray.php
@@ -42,6 +42,7 @@ class IntArray extends NamedTag{
 
 	public function write(NBT $nbt){
 		$nbt->putInt(count($this->value));
-		$nbt->put(pack($nbt->endianness === NBT::LITTLE_ENDIAN ? "V*" : "N*", ...$this->value));
+		$data = pack($nbt->endianness === NBT::LITTLE_ENDIAN ? "V*" : "N*", ...$this->value);
+		$nbt->put($data);
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/nbt/tag/NamedTag.php b/src/pocketmine/nbt/tag/NamedTag.php
index 70fca449e..6ab3d4b81 100644
--- a/src/pocketmine/nbt/tag/NamedTag.php
+++ b/src/pocketmine/nbt/tag/NamedTag.php
@@ -30,15 +30,15 @@ abstract class NamedTag extends Tag{
 	 * @param string                                                      $name
 	 * @param bool|float|double|int|byte|short|array|Compound|Enum|string $value
 	 */
-	public function __construct($name = "", $value = false){
+	public function __construct($name = "", $value = null){
 		$this->name = $name;
-		if($value !== false){
+		if($value !== null){
 			$this->value = $value;
 		}
 	}
 
-	public function getName(){
-		return $this->name === false ? "" : $this->name;
+	public function &getName(){
+		return $this->name;
 	}
 
 	public function setName($name){
diff --git a/src/pocketmine/nbt/tag/String.php b/src/pocketmine/nbt/tag/String.php
index f615b1090..1f0bde0da 100644
--- a/src/pocketmine/nbt/tag/String.php
+++ b/src/pocketmine/nbt/tag/String.php
@@ -27,6 +27,13 @@ use pocketmine\nbt\NBT;
 
 class String extends NamedTag{
 
+	public function __construct($name = "", $value = null){
+		$this->name = $name;
+		if($value !== null){
+			$this->value =& $value;
+		}
+	}
+
 	public function getType(){
 		return NBT::TAG_String;
 	}
diff --git a/src/pocketmine/network/CompressBatchedTask.php b/src/pocketmine/network/CompressBatchedTask.php
index 565fcb9c9..0048dedbe 100644
--- a/src/pocketmine/network/CompressBatchedTask.php
+++ b/src/pocketmine/network/CompressBatchedTask.php
@@ -32,9 +32,17 @@ class CompressBatchedTask extends AsyncTask{
 	public $channel = 0;
 	public $targets = [];
 
+	public function __construct(&$data, array $targets, $level = 7, $channel = 0){
+		$this->data = $data;
+		$this->targets = $targets;
+		$this->level = $level;
+		$this->channel = $channel;
+	}
+
 	public function onRun(){
 		try{
 			$this->final = zlib_encode($this->data, ZLIB_ENCODING_DEFLATE, $this->level);
+			$this->data = null;
 		}catch(\Exception $e){
 
 		}
diff --git a/src/pocketmine/network/RakLibInterface.php b/src/pocketmine/network/RakLibInterface.php
index 2e8b0d31f..f6e1d5677 100644
--- a/src/pocketmine/network/RakLibInterface.php
+++ b/src/pocketmine/network/RakLibInterface.php
@@ -28,7 +28,6 @@ use pocketmine\network\protocol\UnknownPacket;
 use pocketmine\Player;
 use pocketmine\Server;
 use pocketmine\utils\MainLogger;
-use pocketmine\utils\TextFormat;
 use raklib\protocol\EncapsulatedPacket;
 use raklib\RakLib;
 use raklib\server\RakLibServer;
@@ -37,9 +36,6 @@ use raklib\server\ServerInstance;
 
 class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 
-	/** @var \SplFixedArray */
-	private $packetPool;
-
 	/** @var Server */
 	private $server;
 
@@ -145,7 +141,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 	public function handleEncapsulated($identifier, EncapsulatedPacket $packet, $flags){
 		if(isset($this->players[$identifier])){
 			try{
-				$pk = $this->getPacket($packet->buffer);
+				$pk = &$this->getPacket($packet->buffer);
 				$pk->decode();
 				$this->players[$identifier]->handleDataPacket($pk);
 			}catch(\Exception $e){
@@ -250,7 +246,7 @@ class RakLibInterface implements ServerInstance, AdvancedSourceInterface{
 		return null;
 	}
 
-	private function getPacket($buffer){
+	private function &getPacket(&$buffer){
 		$pid = ord($buffer{0});
 
 		if(($data = $this->network->getPacket($pid)) === null){
diff --git a/src/pocketmine/resources/pocketmine.yml b/src/pocketmine/resources/pocketmine.yml
index 9b5e6b306..39fef54bd 100644
--- a/src/pocketmine/resources/pocketmine.yml
+++ b/src/pocketmine/resources/pocketmine.yml
@@ -21,7 +21,48 @@ settings:
  #Number of AsyncTask workers.
  #Used for plugin asynchronous tasks, world generation, compression and web communication.
  #Set this approximately to your number of cores.
- async-workers: 2
+ #If set to auto, it'll try to detect the number of cores (or use 2)
+ async-workers: auto
+
+memory:
+ #Global soft memory limit in megabytes. Set to 0 to disable
+ #This will trigger low-memory-triggers and fire an event to free memory when the usage goes over this
+ global-limit: 512
+
+ #Main thread soft memory limit in megabytes. Set to 0 to disable
+ #This will trigger low-memory-triggers and fire an event to free memory when the usage goes over this
+ main-limit: 320
+
+ #Period in ticks to check memory (default 1 second)
+ check-rate: 20
+
+ #Continue firing low-memory-triggers and event while on low memory
+ continuous-trigger: true
+
+ #Only if memory.continuous-trigger is enabled. Specifies the rate in memory.check-rate steps (default 30 seconds)
+ continuous-trigger-rate: 30
+
+ garbage-collection:
+  #Period in ticks to fire the garbage collector manually (default 10 minutes), set to 0 to disable
+  #This only affect the main thread. Other threads should fire their own collections
+  period: 12000
+
+  #Fire asynchronous tasks to collect garbage from workers
+  collect-async-worker: true
+
+  #Trigger on low memory
+  low-memory-trigger: true
+
+ max-chunks:
+  #Limit of chunks to load per player, overrides chunk-sending.max-chunks
+  trigger-limit: 96
+  #Trigger on low memory
+  low-memory-trigger: true
+
+ world-caches:
+  disable-chunk-cache: true
+  low-memory-trigger: true
+
 
 network:
  #Threshold for batching packets, in bytes. Only these packets will be compressed
@@ -51,9 +92,9 @@ level-settings:
 
 chunk-sending:
  #Amount of chunks sent to players per tick
- per-tick: 8
+ per-tick: 4
  #Amount of chunks sent around each player
- max-chunks: 256
+ max-chunks: 192
  #Amount of chunks that need to be sent before spawning the player
  spawn-threshold: 56
  #Save a serialized copy of the chunk in memory for faster sending
diff --git a/src/pocketmine/scheduler/AsyncPool.php b/src/pocketmine/scheduler/AsyncPool.php
index a58aac9e9..7be1af5d7 100644
--- a/src/pocketmine/scheduler/AsyncPool.php
+++ b/src/pocketmine/scheduler/AsyncPool.php
@@ -47,7 +47,7 @@ class AsyncPool{
 		for($i = 0; $i < $this->size; ++$i){
 			$this->workerUsage[$i] = 0;
 			$this->workers[$i] = new AsyncWorker;
-			$this->workers[$i]->setClassLoader($server->getLoader());
+			$this->workers[$i]->setClassLoader($this->server->getLoader());
 			$this->workers[$i]->start();
 		}
 	}
@@ -56,13 +56,41 @@ class AsyncPool{
 		return $this->size;
 	}
 
-	public function submitTask(AsyncTask $task){
+	public function increaseSize($newSize){
+		$newSize = (int) $newSize;
+		if($newSize > $this->size){
+			$this->size = $newSize;
+			for($i = $this->size; $i < $newSize; ++$i){
+				$this->workerUsage[$i] = 0;
+				$this->workers[$i] = new AsyncWorker;
+				$this->workers[$i]->setClassLoader($this->server->getLoader());
+				$this->workers[$i]->start();
+			}
+		}
+	}
+
+	public function submitTaskToWorker(AsyncTask $task, $worker){
 		if(isset($this->tasks[$task->getTaskId()]) or $task->isGarbage()){
 			return;
 		}
 
+		$worker = (int) $worker;
+		if($worker < 0 or $worker >= $this->size){
+			throw new \InvalidArgumentException("Invalid worker $worker");
+		}
+
 		$this->tasks[$task->getTaskId()] = $task;
 
+		$this->workers[$worker]->stack($task);
+		$this->workerUsage[$worker]++;
+		$this->taskWorkers[$task->getTaskId()] = $worker;
+	}
+
+	public function submitTask(AsyncTask $task){
+		if(isset($this->tasks[$task->getTaskId()]) or $task->isGarbage()){
+			return;
+		}
+
 		$selectedWorker = mt_rand(0, $this->size - 1);
 		$selectedTasks = $this->workerUsage[$selectedWorker];
 		for($i = 0; $i < $this->size; ++$i){
@@ -72,9 +100,7 @@ class AsyncPool{
 			}
 		}
 
-		$this->workers[$selectedWorker]->stack($task);
-		$this->workerUsage[$selectedWorker]++;
-		$this->taskWorkers[$task->getTaskId()] = $selectedWorker;
+		$this->submitTaskToWorker($task, $selectedWorker);
 	}
 
 	private function removeTask(AsyncTask $task){
@@ -85,6 +111,8 @@ class AsyncPool{
 
 		unset($this->tasks[$task->getTaskId()]);
 		unset($this->taskWorkers[$task->getTaskId()]);
+
+		$task->cleanObject();
 	}
 
 	public function removeTasks(){
diff --git a/src/pocketmine/scheduler/AsyncTask.php b/src/pocketmine/scheduler/AsyncTask.php
index e9ca81542..16594aeb5 100644
--- a/src/pocketmine/scheduler/AsyncTask.php
+++ b/src/pocketmine/scheduler/AsyncTask.php
@@ -131,4 +131,10 @@ abstract class AsyncTask extends \Collectable{
 
 	}
 
+	public function cleanObject(){
+		foreach($this as $p => $v){
+			$this->{$p} = null;
+		}
+	}
+
 }
diff --git a/src/pocketmine/scheduler/AsyncWorker.php b/src/pocketmine/scheduler/AsyncWorker.php
index 76ce90c89..79ab59915 100644
--- a/src/pocketmine/scheduler/AsyncWorker.php
+++ b/src/pocketmine/scheduler/AsyncWorker.php
@@ -28,9 +28,11 @@ class AsyncWorker extends Worker{
 	public function run(){
 		$this->registerClassLoader();
 		gc_enable();
+		ini_set("memory_limit", -1);
 
 		global $store;
 		$store = [];
+
 	}
 
 	public function start($options = PTHREADS_INHERIT_NONE){
diff --git a/src/pocketmine/scheduler/GarbageCollectionTask.php b/src/pocketmine/scheduler/GarbageCollectionTask.php
new file mode 100644
index 000000000..e7b353d3d
--- /dev/null
+++ b/src/pocketmine/scheduler/GarbageCollectionTask.php
@@ -0,0 +1,30 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+
+ *
+ *
+*/
+
+namespace pocketmine\scheduler;
+
+class GarbageCollectionTask extends AsyncTask{
+
+	public function onRun(){
+		gc_enable();
+		gc_collect_cycles();
+	}
+}
diff --git a/src/pocketmine/scheduler/ServerScheduler.php b/src/pocketmine/scheduler/ServerScheduler.php
index 1c7fa9a9d..086002841 100644
--- a/src/pocketmine/scheduler/ServerScheduler.php
+++ b/src/pocketmine/scheduler/ServerScheduler.php
@@ -78,6 +78,28 @@ class ServerScheduler{
 		$this->asyncPool->submitTask($task);
 	}
 
+	/**
+	 * Submits an asynchronous task to a specific Worker in the Pool
+	 *
+	 * @param AsyncTask $task
+	 * @param int       $worker
+	 *
+	 * @return void
+	 */
+	public function scheduleAsyncTaskToWorker(AsyncTask $task, $worker){
+		$id = $this->nextId();
+		$task->setTaskId($id);
+		$this->asyncPool->submitTaskToWorker($task, $worker);
+	}
+
+	public function getAsyncTaskPoolSize(){
+		return $this->asyncPool->getSize();
+	}
+
+	public function increaseAsyncTaskPoolSize($newSize){
+		$this->asyncPool->increaseSize($newSize);
+	}
+
 	/**
 	 * @param Task $task
 	 * @param int  $delay
diff --git a/src/pocketmine/utils/Utils.php b/src/pocketmine/utils/Utils.php
index fd0136a1e..6214542f3 100644
--- a/src/pocketmine/utils/Utils.php
+++ b/src/pocketmine/utils/Utils.php
@@ -23,6 +23,7 @@
  * Various Utilities used around the code
  */
 namespace pocketmine\utils;
+use pocketmine\ThreadManager;
 
 /**
  * Big collection of functions
@@ -177,6 +178,76 @@ class Utils{
 		return self::$os;
 	}
 
+
+	public static function getMemoryUsage($advanced = false){
+		$reserved = memory_get_usage();
+		$VmSize = null;
+		$VmRSS = null;
+		if(Utils::getOS() === "linux" or Utils::getOS() === "android"){
+			$status = file_get_contents("/proc/self/status");
+			if(preg_match("/VmRSS:[ \t]+([0-9]+) kB/", $status, $matches) > 0){
+				$VmRSS = $matches[1] * 1024;
+			}
+
+			if(preg_match("/VmSize:[ \t]+([0-9]+) kB/", $status, $matches) > 0){
+				$VmSize = $matches[1] * 1024;
+			}
+		}
+
+		//TODO: more OS
+
+		if($VmRSS === null){
+			$VmRSS = memory_get_usage();
+		}
+
+		if(!$advanced){
+			return $VmRSS;
+		}
+
+		if($VmSize === null){
+			$VmSize = memory_get_usage(true);
+		}
+
+		return [$reserved, $VmRSS, $VmSize];
+	}
+
+	public static function getThreadCount(){
+		if(Utils::getOS() === "linux" or Utils::getOS() === "android"){
+			if(preg_match("/Threads:[ \t]+([0-9]+)/", file_get_contents("/proc/self/status"), $matches) > 0){
+				return (int) $matches[1];
+			}
+		}
+		//TODO: more OS
+
+		return count(ThreadManager::getInstance()->getAll()) + 3; //RakLib + MainLogger + Main Thread
+	}
+
+	public static function getCoreCount(){
+		$processors = 0;
+		switch(Utils::getOS()){
+			case "linux":
+			case "android":
+				if(file_exists("/proc/cpuinfo")){
+					foreach(file("/proc/cpuinfo") as $l){
+						if(preg_match('/^processor[ \t]*:[ \t]*[0-9]+$/m', $l) > 0){
+							++$processors;
+						}
+					}
+				}
+				break;
+			case "bsd":
+				$processors = (int) `sysctl hw.ncpu | awk '{ print $2+1 }'`;
+				break;
+			case "mac":
+				$processors = (int) `sysctl hw.availcpu | awk '{ print $2+1 }'`;
+				break;
+			case "win":
+				$processors = (int) getenv("NUMBER_OF_PROCESSORS");
+				break;
+		}
+		return $processors;
+	}
+
 	/**
 	 * Returns a prettified hexdump
 	 *
diff --git a/src/raklib b/src/raklib
index a35e3d153..cba90210c 160000
--- a/src/raklib
+++ b/src/raklib
@@ -1 +1 @@
-Subproject commit a35e3d1535c327013de94e6d24078dc7573b57ec
+Subproject commit cba90210cd8af5d924e29db6220927a0c896e12a