diff --git a/OpenSim/Framework/Location.cs b/OpenSim/Framework/Location.cs
index 9504e03547..0b888347e7 100644
--- a/OpenSim/Framework/Location.cs
+++ b/OpenSim/Framework/Location.cs
@@ -33,10 +33,10 @@ namespace OpenSim.Framework
     [Serializable]
     public class Location : ICloneable
     {
-        private readonly int m_x;
-        private readonly int m_y;
+        private readonly uint m_x;
+        private readonly uint m_y;
 
-        public Location(int x, int y)
+        public Location(uint x, uint y)
         {
             m_x = x;
             m_y = y;
@@ -44,21 +44,21 @@ namespace OpenSim.Framework
 
         public Location(ulong regionHandle)
         {
-            m_x = (int) regionHandle;
-            m_y = (int) (regionHandle >> 32);
+            m_x =  (uint)(regionHandle >> 32);
+            m_y = (uint)(regionHandle & (ulong)uint.MaxValue);
         }
 
         public ulong RegionHandle
         {
-            get { return Utils.UIntsToLong((uint)m_x, (uint)m_y); }
+            get { return Utils.UIntsToLong(m_x, m_y); }
         }
 
-        public int X
+        public uint X
         {
             get { return m_x; }
         }
 
-        public int Y
+        public uint Y
         {
             get { return m_y; }
         }
diff --git a/OpenSim/Framework/Tests/LocationTest.cs b/OpenSim/Framework/Tests/LocationTest.cs
index a56ecb4049..af5f164d7f 100644
--- a/OpenSim/Framework/Tests/LocationTest.cs
+++ b/OpenSim/Framework/Tests/LocationTest.cs
@@ -51,21 +51,21 @@ namespace OpenSim.Framework.Tests
         [Test]
         public void locationXYRegionHandle()
         {
-            Location TestLocation1 = new Location(256000,256000);
-            Location TestLocation2 = new Location(1099511628032000);
+            Location TestLocation1 = new Location(255000,256000);
+            Location TestLocation2 = new Location(1095216660736000);
             Assert.That(TestLocation1 == TestLocation2);
 
-            Assert.That(TestLocation2.X == 256000 && TestLocation2.Y == 256000, "Test xy location doesn't match regionhandle provided");
+            Assert.That(TestLocation2.X == 255000 && TestLocation2.Y == 256000, "Test xy location doesn't match regionhandle provided");
 
-            Assert.That(TestLocation2.RegionHandle == 1099511628032000,
+            Assert.That(TestLocation2.RegionHandle == 1095216660736000,
                         "Location RegionHandle Property didn't match regionhandle provided in constructor");
 
 
-            TestLocation1 = new Location(256001, 256001);
-            TestLocation2 = new Location(1099511628032000);
+            TestLocation1 = new Location(255001, 256001);
+            TestLocation2 = new Location(1095216660736000);
             Assert.That(TestLocation1 != TestLocation2);
 
-            Assert.That(TestLocation1.Equals(256001, 256001), "Equals(x,y) failed to match the position in the constructor");
+            Assert.That(TestLocation1.Equals(255001, 256001), "Equals(x,y) failed to match the position in the constructor");
 
             Assert.That(TestLocation2.GetHashCode() == (TestLocation2.X.GetHashCode() ^ TestLocation2.Y.GetHashCode()), "GetHashCode failed to produce the expected hashcode");
 
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
index 2a2c819eb3..71b464bc07 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
@@ -698,7 +698,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     {
                         DefaultClientPacketDebugLevel = newDebug;
                         MainConsole.Instance.OutputFormat(
-                            "Debug packet debug for new clients set to {0}", DefaultClientPacketDebugLevel);
+                            "Debug packet debug for new clients set to {0} in {1}", DefaultClientPacketDebugLevel, m_scene.Name);
                     }
                     else
                     {
@@ -1998,7 +1998,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     //
                     // Instead, now wait for data present to be explicitly signalled.  Evidence so far is that with
                     // modern mono it reduces CPU base load since there is no more continuous polling.
-                    m_dataPresentEvent.WaitOne(100);
+                    if (!m_packetSent)
+                        m_dataPresentEvent.WaitOne(100);
 
                     Watchdog.UpdateThread();
                 }
diff --git a/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs b/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs
index 505bb5370e..7b12c81f27 100644
--- a/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs
+++ b/OpenSim/Region/CoreModules/Avatar/Attachments/AttachmentsModule.cs
@@ -29,6 +29,7 @@ using System;
 using System.Collections.Generic;
 using System.Reflection;
 using System.IO;
+using System.Threading;
 using System.Xml;
 using log4net;
 using Mono.Addins;
@@ -51,6 +52,15 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         public int DebugLevel { get; set; }
+
+        /// <summary>
+        /// Period to sleep per 100 prims in order to avoid CPU spikes when an avatar with many attachments logs in
+        /// or many avatars with a medium levels of attachments login simultaneously.
+        /// </summary>
+        /// <remarks>
+        /// A value of 0 will apply no pause.  The pause is specified in milliseconds.
+        /// </remarks>
+        public int ThrottlePer100PrimsRezzed { get; set; }
         
         private Scene m_scene;
         private IInventoryAccessModule m_invAccessModule;
@@ -67,9 +77,15 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
         {
             IConfig config = source.Configs["Attachments"];
             if (config != null)
+            {
                 Enabled = config.GetBoolean("Enabled", true);
+
+                ThrottlePer100PrimsRezzed = config.GetInt("ThrottlePer100PrimsRezzed", 0);
+            }
             else
+            {
                 Enabled = true;
+            }
         }
         
         public void AddRegion(Scene scene)
@@ -88,24 +104,43 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
                 MainConsole.Instance.Commands.AddCommand(
                     "Debug",
                     false,
-                    "debug attachments",
-                    "debug attachments [0|1]",
-                    "Turn on attachments debugging\n"
-                        + "  <= 0 - turns off debugging\n"
-                        + "  >= 1 - turns on attachment message logging\n",
-                    HandleDebugAttachments);
+                    "debug attachments log",
+                    "debug attachments log [0|1]",
+                    "Turn on attachments debug logging",
+                    "  <= 0 - turns off debug logging\n"
+                        + "  >= 1 - turns on attachment message debug logging",
+                    HandleDebugAttachmentsLog);
+
+                MainConsole.Instance.Commands.AddCommand(
+                    "Debug",
+                    false,
+                    "debug attachments throttle",
+                    "debug attachments throttle <ms>",
+                    "Turn on attachments throttling.",
+                    "This requires a millisecond value.  " +
+                    "  == 0 - disable throttling.\n"
+                        + "  > 0 - sleeps for this number of milliseconds per 100 prims rezzed.",
+                    HandleDebugAttachmentsThrottle);
+
+                MainConsole.Instance.Commands.AddCommand(
+                    "Debug",
+                    false,
+                    "debug attachments status",
+                    "debug attachments status",
+                    "Show current attachments debug status",
+                    HandleDebugAttachmentsStatus);
             }
 
             // TODO: Should probably be subscribing to CloseClient too, but this doesn't yet give us IClientAPI
         }
 
-        private void HandleDebugAttachments(string module, string[] args)
+        private void HandleDebugAttachmentsLog(string module, string[] args)
         {
             int debugLevel;
 
-            if (!(args.Length == 3 && int.TryParse(args[2], out debugLevel)))
+            if (!(args.Length == 4 && int.TryParse(args[3], out debugLevel)))
             {
-                MainConsole.Instance.OutputFormat("Usage: debug attachments [0|1]");
+                MainConsole.Instance.OutputFormat("Usage: debug attachments log [0|1]");
             }
             else
             {
@@ -115,6 +150,29 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
             }
         }
 
+        private void HandleDebugAttachmentsThrottle(string module, string[] args)
+        {
+            int ms;
+
+            if (args.Length == 4 && int.TryParse(args[3], out ms))
+            {
+                ThrottlePer100PrimsRezzed = ms;
+                MainConsole.Instance.OutputFormat(
+                    "Attachments rez throttle per 100 prims is now {0} in {1}", ThrottlePer100PrimsRezzed, m_scene.Name);
+
+                return;
+            }
+
+            MainConsole.Instance.OutputFormat("Usage: debug attachments throttle <ms>");
+        }
+
+        private void HandleDebugAttachmentsStatus(string module, string[] args)
+        {
+            MainConsole.Instance.OutputFormat("Settings for {0}", m_scene.Name);
+            MainConsole.Instance.OutputFormat("Debug logging level: {0}", DebugLevel);
+            MainConsole.Instance.OutputFormat("Throttle per 100 prims: {0}ms", ThrottlePer100PrimsRezzed);
+        }
+
         /// <summary>
         /// Listen for client triggered running state changes so that we can persist the script's object if necessary.
         /// </summary>
@@ -275,7 +333,7 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
             List<AvatarAttachment> attachments = sp.Appearance.GetAttachments();
             foreach (AvatarAttachment attach in attachments)
             {
-                uint p = (uint)attach.AttachPoint;
+                uint attachmentPt = (uint)attach.AttachPoint;
 
 //                m_log.DebugFormat(
 //                    "[ATTACHMENTS MODULE]: Doing initial rez of attachment with itemID {0}, assetID {1}, point {2} for {3} in {4}",
@@ -303,14 +361,28 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
 
                     // If we're an NPC then skip all the item checks and manipulations since we don't have an
                     // inventory right now.
-                    RezSingleAttachmentFromInventoryInternal(
-                        sp, sp.PresenceType == PresenceType.Npc ? UUID.Zero : attach.ItemID, attach.AssetID, p, true, null);
+                    SceneObjectGroup objatt 
+                        = RezSingleAttachmentFromInventoryInternal(
+                        sp, sp.PresenceType == PresenceType.Npc ? UUID.Zero : attach.ItemID, attach.AssetID, attachmentPt, true, null);
+
+
+                    if (ThrottlePer100PrimsRezzed > 0)
+                    {
+                        int throttleMs = (int)Math.Round((float)objatt.PrimCount / 100 * ThrottlePer100PrimsRezzed);
+
+                        if (DebugLevel > 0)
+                            m_log.DebugFormat(
+                                "[ATTACHMENTS MODULE]: Throttling by {0}ms after rez of {1} with {2} prims for attachment to {3} on point {4} in {5}",
+                                throttleMs, objatt.Name, objatt.PrimCount, sp.Name, attachmentPt, m_scene.Name);
+
+                        Thread.Sleep(throttleMs);
+                    }
                 }
                 catch (Exception e)
                 {
                     UUID agentId = (sp.ControllingClient == null) ? (UUID)null : sp.ControllingClient.AgentId;
                     m_log.ErrorFormat("[ATTACHMENTS MODULE]: Unable to rez attachment with itemID {0}, assetID {1}, point {2} for {3}: {4}\n{5}",
-                        attach.ItemID, attach.AssetID, p, agentId, e.Message, e.StackTrace);
+                        attach.ItemID, attach.AssetID, attachmentPt, agentId, e.Message, e.StackTrace);
                 }
             }
         }
@@ -984,8 +1056,8 @@ namespace OpenSim.Region.CoreModules.Avatar.Attachments
 
             if (DebugLevel > 0)
                 m_log.DebugFormat(
-                    "[ATTACHMENTS MODULE]: Rezzed single object {0} for attachment to {1} on point {2} in {3}",
-                    objatt.Name, sp.Name, attachmentPt, m_scene.Name);
+                    "[ATTACHMENTS MODULE]: Rezzed single object {0} with {1} prims for attachment to {2} on point {3} in {4}",
+                    objatt.Name, objatt.PrimCount, sp.Name, attachmentPt, m_scene.Name);
 
             // HasGroupChanged is being set from within RezObject.  Ideally it would be set by the caller.
             objatt.HasGroupChanged = false;
diff --git a/bin/OpenSimDefaults.ini b/bin/OpenSimDefaults.ini
index c9a79fce30..286076da19 100644
--- a/bin/OpenSimDefaults.ini
+++ b/bin/OpenSimDefaults.ini
@@ -703,11 +703,18 @@
     ; on every login
     ReuseTextures = false
 
+
 [Attachments]
     ; Controls whether avatar attachments are enabled.
     ; Defaults to true - only set to false for debugging purposes
     Enabled = true
 
+    ; Controls the number of milliseconds that are slept per 100 prims rezzed in attachments
+    ; Experimental setting to control CPU spiking when avatars with many attachments login
+    ; or when multiple avatars with medium level attachments login simultaneously.
+    ; If 0 then no throttling is performed.
+    ThrottlePer100PrimsRezzed = 0;
+
 
 [Mesh]
     ; enable / disable Collada mesh support