diff --git a/OpenRA.FileFormats/OpenRA.FileFormats.csproj b/OpenRA.FileFormats/OpenRA.FileFormats.csproj
index 06edc766a2..4b712ccb84 100644
--- a/OpenRA.FileFormats/OpenRA.FileFormats.csproj
+++ b/OpenRA.FileFormats/OpenRA.FileFormats.csproj
@@ -114,6 +114,7 @@
     <Compile Include="FileFormats\Blast.cs" />
     <Compile Include="Filesystem\ZipFile.cs" />
     <Compile Include="InstallUtils.cs" />
+    <Compile Include="Primitives\Cached.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
@@ -123,4 +124,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
\ No newline at end of file
+</Project>
diff --git a/OpenRA.FileFormats/Primitives/Cached.cs b/OpenRA.FileFormats/Primitives/Cached.cs
new file mode 100644
index 0000000000..8823626eda
--- /dev/null
+++ b/OpenRA.FileFormats/Primitives/Cached.cs
@@ -0,0 +1,60 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made 
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+
+namespace OpenRA.FileFormats
+{
+	public class Cached<T>
+	{
+		Func<T> p;
+		T value;
+		bool hasValue;
+
+		public Cached(Func<T> p)
+		{
+			if (p == null)
+				throw new ArgumentNullException();
+
+			this.p = p;
+		}
+
+		public T Value
+		{
+			get
+			{
+				if (hasValue)
+					return value;
+
+				value = p();
+				hasValue = true;
+				return value;
+			}
+		}
+
+        public void Force()
+        {
+            #pragma warning disable 0168
+			var ignored = Value;
+			#pragma warning restore 0168
+        }
+		
+		public void Invalidate()
+		{
+			hasValue = false;
+		}
+	}
+
+	public static class Cached
+	{
+		public static Cached<T> New<T>(Func<T> p) { return new Cached<T>(p); }
+	}
+}
+
diff --git a/OpenRA.Game/Actor.cs b/OpenRA.Game/Actor.cs
index 39e2a9055e..890f0d158a 100755
--- a/OpenRA.Game/Actor.cs
+++ b/OpenRA.Game/Actor.cs
@@ -28,6 +28,8 @@ namespace OpenRA
 		IOccupySpace OccupiesSpace;
 		IHasLocation HasLocation;
 		Lazy<IMove> Move;
+		public Cached<RectangleF> Bounds;
+		public Cached<RectangleF> ExtendedBounds;
 
 		public int2 Location
 		{ get {
@@ -84,10 +86,16 @@ namespace OpenRA
 
 			ApplyIRender = x => x.Render(this);
 			ApplyRenderModifier = (m, p) => p.ModifyRender(this, m);
+			
+			Bounds = Cached.New( () => CalculateBounds(false) );
+			ExtendedBounds = Cached.New( () => CalculateBounds(true) );
 		}
 
 		public void Tick()
 		{
+			Bounds.Invalidate();
+			ExtendedBounds.Invalidate();
+			
 			currentActivity = Util.RunActivity( this, currentActivity );
 		}
 
@@ -112,7 +120,7 @@ namespace OpenRA
 		// vertically to altitude = 0 to support FindUnitsInCircle queries
 		// When false, the bounding box is given for the actor
 		// at its current altitude
-		public RectangleF GetBounds(bool useAltitude)
+		RectangleF CalculateBounds(bool useAltitude)
 		{
 			var size = Size.Value;
 			var loc = CenterLocation - 0.5f * size;
diff --git a/OpenRA.Game/Graphics/WorldRenderer.cs b/OpenRA.Game/Graphics/WorldRenderer.cs
index 9280b65dd8..f25fde4cea 100644
--- a/OpenRA.Game/Graphics/WorldRenderer.cs
+++ b/OpenRA.Game/Graphics/WorldRenderer.cs
@@ -125,7 +125,7 @@ namespace OpenRA.Graphics
 
 		public void DrawSelectionBox(Actor selectedUnit, Color c)
 		{
-			var bounds = selectedUnit.GetBounds(false);
+			var bounds = selectedUnit.Bounds.Value;
 
 			var xy = new float2(bounds.Left, bounds.Top);
 			var Xy = new float2(bounds.Right, bounds.Top);
diff --git a/OpenRA.Game/Traits/Selectable.cs b/OpenRA.Game/Traits/Selectable.cs
index 4c48e327a9..4c374720cb 100644
--- a/OpenRA.Game/Traits/Selectable.cs
+++ b/OpenRA.Game/Traits/Selectable.cs
@@ -30,7 +30,7 @@ namespace OpenRA.Traits
 		
 		public void RenderAfterWorld (WorldRenderer wr, Actor self)
 		{
-			var bounds = self.GetBounds(false);
+			var bounds = self.Bounds.Value;
 			Color selectionColor = Color.White;
 
 			var xy = new float2(bounds.Left, bounds.Top);
@@ -55,7 +55,7 @@ namespace OpenRA.Traits
 
 		public void DrawRollover(WorldRenderer wr, Actor self)
 		{
-			var bounds = self.GetBounds(false);
+			var bounds = self.Bounds.Value;
 			
 			var xy = new float2(bounds.Left, bounds.Top);
 			var Xy = new float2(bounds.Right, bounds.Top);
@@ -184,10 +184,12 @@ namespace OpenRA.Traits
 				var thisRow = pips.GetPips(self);
 				if (thisRow == null)
 					continue;
+				
+				var width = self.Bounds.Value.Width;
 
 				foreach (var pip in thisRow)
 				{
-					if (pipxyOffset.X+5 > self.GetBounds(false).Width)
+					if (pipxyOffset.X+5 > width)
 					{
 						pipxyOffset.X = 0;
 						pipxyOffset.Y -= 4;
diff --git a/OpenRA.Game/Traits/World/SpatialBins.cs b/OpenRA.Game/Traits/World/SpatialBins.cs
index 647499ae92..1d7b6a3f1b 100644
--- a/OpenRA.Game/Traits/World/SpatialBins.cs
+++ b/OpenRA.Game/Traits/World/SpatialBins.cs
@@ -47,7 +47,7 @@ namespace OpenRA.Traits
 
 			foreach (var a in self.World.ActorsWithTrait<IHasLocation>())
 			{
-				var bounds = a.Actor.GetBounds(true);
+				var bounds = a.Actor.ExtendedBounds.Value;
 
 				if (bounds.Right <= Game.CellSize * self.World.Map.Bounds.Left) continue;
 				if (bounds.Bottom <= Game.CellSize * self.World.Map.Bounds.Top) continue;
@@ -81,7 +81,7 @@ namespace OpenRA.Traits
 
 			return ActorsInBins(a.X / scale, b.X / scale, a.Y / scale, b.Y / scale)
 				.Distinct()
-				.Where(u => u.IsInWorld && u.GetBounds(true).IntersectsWith(r));
+				.Where(u => u.IsInWorld && u.ExtendedBounds.Value.IntersectsWith(r));
 		}
 	}
 }
diff --git a/OpenRA.Game/WorldUtils.cs b/OpenRA.Game/WorldUtils.cs
index 9432f212e4..a8db341db5 100755
--- a/OpenRA.Game/WorldUtils.cs
+++ b/OpenRA.Game/WorldUtils.cs
@@ -45,7 +45,7 @@ namespace OpenRA
 
 				var rect = new RectangleF(min.X, min.Y, max.X - min.X, max.Y - min.Y);
 
-				var inBox = actors.Where(x => x.GetBounds(true).IntersectsWith(rect));
+				var inBox = actors.Where(x => x.ExtendedBounds.Value.IntersectsWith(rect));
 
 				return inBox.Where(x => (x.CenterLocation - a).LengthSquared < r * r);
 			}
diff --git a/OpenRA.Mods.RA/GainsExperience.cs b/OpenRA.Mods.RA/GainsExperience.cs
index 1da8eaa9a5..e8ed897c43 100644
--- a/OpenRA.Mods.RA/GainsExperience.cs
+++ b/OpenRA.Mods.RA/GainsExperience.cs
@@ -107,8 +107,7 @@ namespace OpenRA.Mods.RA
 			foreach (var r in rs)
 				yield return r;
 
-			RankAnim.Tick();	// hack
-			var bounds = self.GetBounds(false);
+			var bounds = self.Bounds.Value;
 			yield return new Renderable(RankAnim.Image,
 				new float2(bounds.Right - 6, bounds.Bottom - 8), "effect", self.CenterLocation.Y);
 		}