diff --git a/parts/automation/UpgradeInventory.java b/parts/automation/UpgradeInventory.java
index 5087efc7..69e960da 100644
--- a/parts/automation/UpgradeInventory.java
+++ b/parts/automation/UpgradeInventory.java
@@ -13,6 +13,7 @@ import appeng.util.Platform;
 public class UpgradeInventory extends AppEngInternalInventory implements IAEAppEngInventory
 {
 
+	private boolean cached = false;
 	private int FuzzyUpgrades = 0;
 	private int SpeedUpgrades = 0;
 	private int RedstoneUpgrades = 0;
@@ -32,6 +33,12 @@ public class UpgradeInventory extends AppEngInternalInventory implements IAEAppE
 		return true;
 	}
 
+	@Override
+	public void setInventorySlotContents(int slot, ItemStack newItemStack)
+	{
+		super.setInventorySlotContents( slot, newItemStack );
+	}
+
 	@Override
 	public boolean isItemValidForSlot(int i, ItemStack itemstack)
 	{
@@ -51,6 +58,7 @@ public class UpgradeInventory extends AppEngInternalInventory implements IAEAppE
 
 	private void updateUpgradeInfo()
 	{
+		cached = true;
 		CapacityUpgrades = RedstoneUpgrades = SpeedUpgrades = FuzzyUpgrades = 0;
 
 		for (ItemStack is : this)
@@ -86,6 +94,9 @@ public class UpgradeInventory extends AppEngInternalInventory implements IAEAppE
 
 	public int getInstalledUpgrades(Upgrades u)
 	{
+		if ( !cached )
+			updateUpgradeInfo();
+
 		switch (u)
 		{
 		case CAPACITY:
@@ -104,8 +115,7 @@ public class UpgradeInventory extends AppEngInternalInventory implements IAEAppE
 	@Override
 	public void onChangeInventory(IInventory inv, int slot, InvOperation mc, ItemStack removedStack, ItemStack newStack)
 	{
-		updateUpgradeInfo();
-
+		cached = false;
 		if ( parent != null && Platform.isServer() )
 			parent.onChangeInventory( inv, slot, mc, removedStack, newStack );
 	}
diff --git a/tile/inventory/AppEngInternalAEInventory.java b/tile/inventory/AppEngInternalAEInventory.java
index f3c231e8..7d5ae7b8 100644
--- a/tile/inventory/AppEngInternalAEInventory.java
+++ b/tile/inventory/AppEngInternalAEInventory.java
@@ -10,6 +10,7 @@ import appeng.api.AEApi;
 import appeng.api.storage.data.IAEItemStack;
 import appeng.util.Platform;
 import appeng.util.item.AEItemStack;
+import appeng.util.iterators.AEInvIterator;
 import appeng.util.iterators.InvIterator;
 
 public class AppEngInternalAEInventory implements IInventory, Iterable<ItemStack>
@@ -237,4 +238,9 @@ public class AppEngInternalAEInventory implements IInventory, Iterable<ItemStack
 	{
 		return new InvIterator( this );
 	}
+
+	public Iterator<IAEItemStack> aeiterator()
+	{
+		return new AEInvIterator( this );
+	}
 }
diff --git a/util/iterators/AEInvIterator.java b/util/iterators/AEInvIterator.java
new file mode 100644
index 00000000..c7720cff
--- /dev/null
+++ b/util/iterators/AEInvIterator.java
@@ -0,0 +1,39 @@
+package appeng.util.iterators;
+
+import java.util.Iterator;
+
+import appeng.api.storage.data.IAEItemStack;
+import appeng.tile.inventory.AppEngInternalAEInventory;
+
+public class AEInvIterator implements Iterator<IAEItemStack>
+{
+
+	final AppEngInternalAEInventory inv;
+	final int size;
+
+	int x = 0;
+
+	public AEInvIterator(AppEngInternalAEInventory i) {
+		inv = i;
+		size = inv.getSizeInventory();
+	}
+
+	@Override
+	public boolean hasNext()
+	{
+		return x < size;
+	}
+
+	@Override
+	public IAEItemStack next()
+	{
+		return inv.getAEStackInSlot( x++ );
+	}
+
+	@Override
+	public void remove()
+	{
+		throw new RuntimeException( "no..." );
+	}
+
+}