diff --git a/src/main/java/net/minestom/server/entity/pathfinding/AStarPathfinder.java b/src/main/java/net/minestom/server/entity/pathfinding/AStarPathfinder.java
index 0e7cb8370..b4cfacdc6 100644
--- a/src/main/java/net/minestom/server/entity/pathfinding/AStarPathfinder.java
+++ b/src/main/java/net/minestom/server/entity/pathfinding/AStarPathfinder.java
@@ -21,6 +21,7 @@ public class AStarPathfinder {
     public static LinkedList<BlockPosition> getPath(Instance instance,
                                                     BlockPosition start, BlockPosition end,
                                                     int maxCheck) {
+        long time = System.nanoTime();
         List<Node> open = new ArrayList<>();
         List<Node> closed = new ArrayList<>();
 
@@ -37,6 +38,7 @@ public class AStarPathfinder {
             closed.add(current);
 
             if (isTargetNode(end, current)) {
+                System.out.println("found in: " + (System.nanoTime() - time) + " ns");
                 return buildPath(current);
             }
 
diff --git a/src/main/java/net/minestom/server/instance/Chunk.java b/src/main/java/net/minestom/server/instance/Chunk.java
index 835b5e7cb..4716ae94e 100644
--- a/src/main/java/net/minestom/server/instance/Chunk.java
+++ b/src/main/java/net/minestom/server/instance/Chunk.java
@@ -37,9 +37,9 @@ public class Chunk implements Viewable {
     private Biome biome;
     private int chunkX, chunkZ;
 
-    // blocks id based on coord
-    private short[][][] blocksId = new short[CHUNK_SIZE_X][CHUNK_SIZE_Y][CHUNK_SIZE_Z];
-    private short[][][] customBlocksId = new short[CHUNK_SIZE_X][CHUNK_SIZE_Y][CHUNK_SIZE_Z];
+    // blocks id based on coord, see Chunk#getBlockIndex
+    private short[] blocksId = new short[CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z];
+    private short[] customBlocksId = new short[CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z];
 
     // Used to get all blocks with data (no null)
     // Key is still chunk coord
@@ -98,7 +98,7 @@ public class Chunk implements Viewable {
         } else {
             // Block has been deleted, clear cache and return
 
-            this.blocksId[x][y][z] = 0; // Set to air
+            this.blocksId[getBlockIndex(x, y, z)] = 0; // Set to air
             //this.blocks.remove(index);
 
             this.blocksData.remove(index);
@@ -147,17 +147,17 @@ public class Chunk implements Viewable {
     }
 
     public short getBlockId(int x, int y, int z) {
-        short id = blocksId[x][y][z];
+        short id = blocksId[getBlockIndex(x, y, z)];
         return id;
     }
 
     public short getCustomBlockId(int x, int y, int z) {
-        short id = customBlocksId[x][y][z];
+        short id = customBlocksId[getBlockIndex(x, y, z)];
         return id;
     }
 
     public CustomBlock getCustomBlock(int x, int y, int z) {
-        short id = customBlocksId[x][y][z];
+        short id = customBlocksId[getBlockIndex(x, y, z)];
         return id != 0 ? BLOCK_MANAGER.getBlock(id) : null;
     }
 
@@ -167,8 +167,8 @@ public class Chunk implements Viewable {
     }
 
     protected void refreshBlockValue(int x, int y, int z, short blockId, short customId) {
-        this.blocksId[x][y][z] = blockId;
-        this.customBlocksId[x][y][z] = customId;
+        this.blocksId[getBlockIndex(x, y, z)] = blockId;
+        this.customBlocksId[getBlockIndex(x, y, z)] = customId;
     }
 
     protected void refreshBlockValue(int x, int y, int z, short blockId) {
@@ -340,4 +340,9 @@ public class Chunk implements Viewable {
     public Set<Player> getViewers() {
         return Collections.unmodifiableSet(viewers);
     }
+
+    private int getBlockIndex(int x, int y, int z) {
+        int index = (((y * 16) + x) * 16) + z;
+        return index;
+    }
 }
\ No newline at end of file
diff --git a/src/main/java/net/minestom/server/instance/InstanceContainer.java b/src/main/java/net/minestom/server/instance/InstanceContainer.java
index 3e60527d1..4af028753 100644
--- a/src/main/java/net/minestom/server/instance/InstanceContainer.java
+++ b/src/main/java/net/minestom/server/instance/InstanceContainer.java
@@ -106,10 +106,12 @@ public class InstanceContainer extends Instance {
     public void refreshBlockId(int x, int y, int z, short blockId) {
         Chunk chunk = getChunkAt(x, z);
         synchronized (chunk) {
-            byte chunkX = (byte) (x % 16);
-            byte chunkY = (byte) y;
-            byte chunkZ = (byte) (z % 16);
-            int index = SerializerUtils.chunkCoordToIndex(chunkX, chunkY, chunkZ);
+            int chunkX = x % 16;
+            int chunkY = y;
+            int chunkZ = z % 16;
+
+            chunkX = ChunkUtils.refreshChunkXZ(chunkX);
+            chunkZ = ChunkUtils.refreshChunkXZ(chunkZ);
 
             chunk.refreshBlockValue(chunkX, chunkY, chunkZ, blockId);