diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 8c279ec7ab..1f19227588 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -1090,22 +1090,28 @@ public abstract class EntityLiving extends Entity {
             --this.aN;
             this.setPosition(d0, d1, d2);
             this.c(this.yaw, this.pitch);
-            List list = this.world.getCubes(this, this.boundingBox.shrink(0.03125D, 0.0D, 0.03125D));
-
-            if (list.size() > 0) {
-                double d4 = 0.0D;
-
-                for (int i = 0; i < list.size(); ++i) {
-                    AxisAlignedBB axisalignedbb = (AxisAlignedBB) list.get(i);
-
-                    if (axisalignedbb.e > d4) {
-                        d4 = axisalignedbb.e;
-                    }
-                }
-
-                d1 += d4 - this.boundingBox.b;
+            // CraftBukkit start - getCubes is expensive, use an approximation
+            if (this.world.getTypeId(MathHelper.floor(d0), MathHelper.floor(d1), MathHelper.floor(d2)) != 0) {
+                d1 += 1.0D;
                 this.setPosition(d0, d1, d2);
             }
+            //List list = this.world.getCubes(this, this.boundingBox.shrink(0.03125D, 0.0D, 0.03125D));
+
+            //if (list.size() > 0) {
+            //    double d4 = 0.0D;
+
+            //    for (int i = 0; i < list.size(); ++i) {
+            //        AxisAlignedBB axisalignedbb = (AxisAlignedBB) list.get(i);
+
+            //        if (axisalignedbb.e > d4) {
+            //            d4 = axisalignedbb.e;
+            //        }
+            //    }
+
+            //    d1 += d4 - this.boundingBox.b;
+            //    this.setPosition(d0, d1, d2);
+            //}
+            // CraftBukkit end
         }
 
         // MethodProfiler.a("ai"); // CraftBukkit - not in production code
@@ -1116,13 +1122,13 @@ public abstract class EntityLiving extends Entity {
             this.aY = 0.0F;
         } else if (this.aF()) {
             if (this.c_()) {
-                MethodProfiler.a("newAi");
+                // MethodProfiler.a("newAi"); // CraftBukkit - not in production code
                 this.z_();
-                MethodProfiler.a();
+                // MethodProfiler.a(); // CraftBukkit - not in production code
             } else {
-                MethodProfiler.a("oldAi");
+                // MethodProfiler.a("oldAi"); // CraftBukkit - not in production code
                 this.d_();
-                MethodProfiler.a();
+                // MethodProfiler.a(); // CraftBukkit - not in production code
                 this.X = this.yaw;
             }
         }
@@ -1234,10 +1240,14 @@ public abstract class EntityLiving extends Entity {
         this.m.a();
         //MethodProfiler.a(); // CraftBukkit - not in production code
         //MethodProfiler.a("targetSelector"); // CraftBukkit - not in production code
-        this.targetSelector.a();
+        // CraftBukkit start - run goal selectors every other tick
+        if ((this.aV & 1) == 0) {
+            this.targetSelector.a();
         //MethodProfiler.a(); // CraftBukkit - not in production code
         //MethodProfiler.a("goalSelector"); // CraftBukkit - not in production code
-        this.goalSelector.a();
+            this.goalSelector.a();
+        }
+        // CraftBukkit end
         //MethodProfiler.a(); // CraftBukkit - not in production code
         //MethodProfiler.a("navigation"); // CraftBukkit - not in production code
         this.navigation.d();
diff --git a/src/main/java/net/minecraft/server/PathfinderGoalSelector.java b/src/main/java/net/minecraft/server/PathfinderGoalSelector.java
index 43dc1b9f20..054777c412 100644
--- a/src/main/java/net/minecraft/server/PathfinderGoalSelector.java
+++ b/src/main/java/net/minecraft/server/PathfinderGoalSelector.java
@@ -7,6 +7,7 @@ public class PathfinderGoalSelector {
 
     private ArrayList a = new ArrayList();
     private ArrayList b = new ArrayList();
+    private ArrayList arraylist = new ArrayList(); // CraftBukkit - create list for object reuse
 
     public PathfinderGoalSelector() {}
 
@@ -15,11 +16,12 @@ public class PathfinderGoalSelector {
     }
 
     public void a() {
-        ArrayList arraylist = new ArrayList();
-        Iterator iterator = this.a.iterator();
+        //ArrayList arraylist = new ArrayList(); // CraftBukkit
+        arraylist.clear(); // CraftBukkit - prepare reused list
 
-        while (iterator.hasNext()) {
-            PathfinderGoalSelectorItem pathfindergoalselectoritem = (PathfinderGoalSelectorItem) iterator.next();
+        // CraftBukkit start - don't use iterators for private fields
+        for (int i = 0; i < this.a.size(); i++) {
+            PathfinderGoalSelectorItem pathfindergoalselectoritem = (PathfinderGoalSelectorItem) this.a.get(i);
             boolean flag = this.b.contains(pathfindergoalselectoritem);
 
             if (flag) {
@@ -36,6 +38,7 @@ public class PathfinderGoalSelector {
                 this.b.add(pathfindergoalselectoritem);
             }
         }
+        // CraftBukkit end
 
         boolean flag1 = false;
 
@@ -46,8 +49,10 @@ public class PathfinderGoalSelector {
         Iterator iterator1;
         PathfinderGoalSelectorItem pathfindergoalselectoritem1;
 
-        for (iterator1 = arraylist.iterator(); iterator1.hasNext(); pathfindergoalselectoritem1.a.c()) {
-            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) iterator1.next();
+        //CraftBukkit start - don't use iterators for private fields
+        for (int i = 0; i < arraylist.size(); i++) {
+            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) arraylist.get(i);
+            pathfindergoalselectoritem1.a.c();
             if (flag1) {
                 System.out.println(pathfindergoalselectoritem1.a.toString() + ", ");
             }
@@ -57,19 +62,20 @@ public class PathfinderGoalSelector {
             System.out.println("Running: ");
         }
 
-        for (iterator1 = this.b.iterator(); iterator1.hasNext(); pathfindergoalselectoritem1.a.e()) {
-            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) iterator1.next();
+        for (int i = 0; i < this.b.size(); i++) {
+            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) this.b.get(i);
+            pathfindergoalselectoritem1.a.e();
             if (flag1) {
                 System.out.println(pathfindergoalselectoritem1.a.toString());
             }
         }
+        // CraftBukkit end
     }
 
     private boolean a(PathfinderGoalSelectorItem pathfindergoalselectoritem) {
-        Iterator iterator = this.a.iterator();
-
-        while (iterator.hasNext()) {
-            PathfinderGoalSelectorItem pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) iterator.next();
+        // CraftBukkit start - don't use iterators for private fields
+        for (int i = 0; i < this.a.size(); i++) {
+            PathfinderGoalSelectorItem pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) this.a.get(i);
 
             if (pathfindergoalselectoritem1 != pathfindergoalselectoritem) {
                 if (pathfindergoalselectoritem.b >= pathfindergoalselectoritem1.b) {
@@ -81,6 +87,7 @@ public class PathfinderGoalSelector {
                 }
             }
         }
+        // CraftBukkit end
 
         return true;
     }