diff --git a/common/src/main/java/us/myles/ViaVersion/api/minecraft/chunks/NibbleArray.java b/common/src/main/java/us/myles/ViaVersion/api/minecraft/chunks/NibbleArray.java
index 8245d2a8c..4cfeddccc 100644
--- a/common/src/main/java/us/myles/ViaVersion/api/minecraft/chunks/NibbleArray.java
+++ b/common/src/main/java/us/myles/ViaVersion/api/minecraft/chunks/NibbleArray.java
@@ -67,11 +67,12 @@ public class NibbleArray {
      * @param value The desired value
      */
     public void set(int index, int value) {
-        index /= 2;
         if (index % 2 == 0) {
-            handle[index] = (byte) (handle[index] & 0xF0 | value & 0xF);
+            index /= 2;
+            handle[index] = (byte) ((handle[index] & 0xF0) | (value & 0xF));
         } else {
-            handle[index] = (byte) (handle[index] & 0xF | (value & 0xF) << 4);
+            index /= 2;
+            handle[index] = (byte) ((handle[index] & 0xF) | ((value & 0xF) << 4));
         }
     }
 
diff --git a/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/packets/WorldPackets.java b/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/packets/WorldPackets.java
index be1d08ea2..5593028f0 100644
--- a/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/packets/WorldPackets.java
+++ b/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/packets/WorldPackets.java
@@ -175,12 +175,13 @@ public class WorldPackets {
 
                         if (Via.getConfig().isServersideBlockConnections()) {
                             UserConnection userConnection = wrapper.user();
+
+                            ConnectionData.updateBlockStorage(userConnection, position, newId);
+
                             if (ConnectionData.connects(newId)) {
                                 newId = ConnectionData.connect(userConnection, position, newId);
                             }
 
-                            ConnectionData.updateBlockStorage(userConnection, position, newId);
-
                             ConnectionData.update(userConnection, position);
                         }
 
diff --git a/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/storage/BlockConnectionStorage.java b/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/storage/BlockConnectionStorage.java
index ad0a9e595..1694e2af9 100644
--- a/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/storage/BlockConnectionStorage.java
+++ b/common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/storage/BlockConnectionStorage.java
@@ -1,42 +1,88 @@
 package us.myles.ViaVersion.protocols.protocol1_13to1_12_2.storage;
 
-import lombok.Data;
-import lombok.EqualsAndHashCode;
 import us.myles.ViaVersion.api.Pair;
+import us.myles.ViaVersion.api.Via;
 import us.myles.ViaVersion.api.data.StoredObject;
 import us.myles.ViaVersion.api.data.UserConnection;
 import us.myles.ViaVersion.api.minecraft.Position;
+import us.myles.ViaVersion.api.minecraft.chunks.NibbleArray;
+import us.myles.ViaVersion.protocols.protocol1_13to1_12_2.data.MappingData;
+import us.myles.ViaVersion.protocols.protocol1_13to1_12_2.packets.WorldPackets;
 
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
 import java.util.HashMap;
 import java.util.Map;
 
 public class BlockConnectionStorage extends StoredObject {
-    private Map<Pair<Integer, Integer>, Map<BlockPositon, Integer>> blockStorage = new HashMap<>();
+    private Map<Long, Pair<byte[], NibbleArray>> blockStorage = createLongObjectMap();
+
+    private static Constructor<?> fastUtilLongObjectHashMap;
+    private static HashMap<Short, Short> reverseBlockMappings;
+
+    static {
+        try {
+            fastUtilLongObjectHashMap = Class.forName("it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap").getConstructor();
+            Via.getPlatform().getLogger().info("Using FastUtil Long2ObjectOpenHashMap for block connections");
+        } catch (ClassNotFoundException | NoSuchMethodException ignored) {
+        }
+        reverseBlockMappings = new HashMap<>();
+        for (int i = 0; i < 4096; i++) {
+            int newBlock = MappingData.blockMappings.getNewBlock(i);
+            if (newBlock != -1) reverseBlockMappings.put((short) newBlock, (short) i);
+        }
+    }
 
     public BlockConnectionStorage(UserConnection user) {
         super(user);
     }
 
     public void store(Position position, int blockState) {
-        Pair pair = getPair(position);
-        Map<BlockPositon, Integer> map = getChunkMap(pair);
-        map.put(new BlockPositon(position), blockState);
+        Short mapping = reverseBlockMappings.get((short) blockState);
+        if (mapping == null) return;
+        blockState = mapping;
+        long pair = getChunkSectionIndex(position);
+        Pair<byte[], NibbleArray> map = getChunkSection(pair, (blockState & 0xF) != 0);
+        int blockIndex = encodeBlockPos(position);
+        map.getKey()[blockIndex] = (byte) (blockState >> 4);
+        NibbleArray nibbleArray = map.getValue();
+        if (nibbleArray != null) nibbleArray.set(blockIndex, blockState);
     }
 
     public int get(Position position) {
-        Pair pair = getPair(position);
-        Map<BlockPositon, Integer> map = getChunkMap(pair);
-        BlockPositon blockPositon = new BlockPositon(position);
-        return map.containsKey(blockPositon) ? map.get(blockPositon) : 0;
+        long pair = getChunkSectionIndex(position);
+        Pair<byte[], NibbleArray> map = blockStorage.get(pair);
+        if (map == null) return 0;
+        short blockPosition = encodeBlockPos(position);
+        NibbleArray nibbleArray = map.getValue();
+        return WorldPackets.toNewId(
+                ((map.getKey()[blockPosition] & 0xFF) << 4)
+                | (nibbleArray == null ? 0 : nibbleArray.get(blockPosition))
+        );
     }
 
     public void remove(Position position) {
-        Pair pair = getPair(position);
-        Map<BlockPositon, Integer> map = getChunkMap(pair);
-        map.remove(new BlockPositon(position));
-        if (map.isEmpty()) {
-            blockStorage.remove(pair);
+        long pair = getChunkSectionIndex(position);
+        Pair<byte[], NibbleArray> map = blockStorage.get(pair);
+        if (map == null) return;
+        int blockIndex = encodeBlockPos(position);
+        NibbleArray nibbleArray = map.getValue();
+        if (nibbleArray != null) {
+            nibbleArray.set(blockIndex, 0);
+            boolean allZero = true;
+            for (int i = 0; i < 4096; i++) {
+                if (nibbleArray.get(i) != 0) {
+                    allZero = false;
+                    break;
+                }
+            }
+            if (allZero) map.setValue(null);
         }
+        map.getKey()[blockIndex] = 0;
+        for (short entry : map.getKey()) {
+            if (entry != 0) return;
+        }
+        blockStorage.remove(pair);
     }
 
     public void clear() {
@@ -44,33 +90,47 @@ public class BlockConnectionStorage extends StoredObject {
     }
 
     public void unloadChunk(int x, int z) {
-        blockStorage.remove(new Pair<>(x, z));
+        for (int y = 0; y < 256; y += 16) {
+            blockStorage.remove(getChunkSectionIndex(x, y, z));
+        }
     }
 
-    private Map<BlockPositon, Integer> getChunkMap(Pair pair) {
-        Map<BlockPositon, Integer> map = blockStorage.get(pair);
+    private Pair<byte[], NibbleArray> getChunkSection(long index, boolean requireNibbleArray) {
+        Pair<byte[], NibbleArray> map = blockStorage.get(index);
         if (map == null) {
-            map = new HashMap<>();
-            blockStorage.put(pair, map);
+            map = new Pair<>(new byte[4096], null);
+            blockStorage.put(index, map);
+        }
+        if (map.getValue() == null && requireNibbleArray) {
+            map.setValue(new NibbleArray(4096));
         }
         return map;
     }
 
-    private Pair<Integer, Integer> getPair(Position position) {
-        int chunkX = (int) (position.getX() >> 4);
-        int chunkZ = (int) (position.getZ() >> 4);
-        return new Pair<>(chunkX, chunkZ);
+    private long getChunkSectionIndex(int x, int y, int z) {
+        return (((x >> 4) & 0x3FFFFFFL) << 38) | (((y >> 4) & 0xFFFL) << 26) | ((z >> 4) & 0x3FFFFFFL);
     }
 
-    @EqualsAndHashCode
-    @Data
-    private class BlockPositon {
-        int x, y, z;
+    private long getChunkSectionIndex(Position position) {
+        return getChunkSectionIndex(position.getX().intValue(), position.getY().intValue(), position.getZ().intValue());
+    }
 
-        public BlockPositon(Position position) {
-            x = position.getX().intValue();
-            y = position.getY().intValue();
-            z = position.getZ().intValue();
+    private short encodeBlockPos(int x, int y, int z) {
+        return (short) (((y & 0xF) << 8) | ((x & 0xF) << 4) | (z & 0xF));
+    }
+
+    private short encodeBlockPos(Position pos) {
+        return encodeBlockPos(pos.getX().intValue(), pos.getY().intValue(), pos.getZ().intValue());
+    }
+
+    private <T> Map<Long, T> createLongObjectMap() {
+        if (fastUtilLongObjectHashMap != null) {
+            try {
+                return (Map<Long, T>) fastUtilLongObjectHashMap.newInstance();
+            } catch (IllegalAccessException | InstantiationException | InvocationTargetException e) {
+                e.printStackTrace();
+            }
         }
+        return new HashMap<>();
     }
 }