diff --git a/RombaSharp/RombaSharp.Helpers.cs b/RombaSharp/RombaSharp.Helpers.cs
index 9c7e8f89..b806e419 100644
--- a/RombaSharp/RombaSharp.Helpers.cs
+++ b/RombaSharp/RombaSharp.Helpers.cs
@@ -629,7 +629,7 @@ namespace RombaSharp
 
 			// Once we have both, check for any new files
 			List<string> dupehashes = new List<string>();
-			List<string> keys = depot.Keys.ToList();
+			List<string> keys = depot.Keys;
 			foreach (string key in keys)
 			{
 				List<DatItem> roms = depot[key];
diff --git a/SabreTools.Library/DatFiles/AttractMode.cs b/SabreTools.Library/DatFiles/AttractMode.cs
index 2e26f219..6b32976f 100644
--- a/SabreTools.Library/DatFiles/AttractMode.cs
+++ b/SabreTools.Library/DatFiles/AttractMode.cs
@@ -141,7 +141,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/ClrMamePro.cs b/SabreTools.Library/DatFiles/ClrMamePro.cs
index dc81cf66..c641c858 100644
--- a/SabreTools.Library/DatFiles/ClrMamePro.cs
+++ b/SabreTools.Library/DatFiles/ClrMamePro.cs
@@ -654,7 +654,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/DatFile.cs b/SabreTools.Library/DatFiles/DatFile.cs
index a0a823e2..1aa30ab2 100644
--- a/SabreTools.Library/DatFiles/DatFile.cs
+++ b/SabreTools.Library/DatFiles/DatFile.cs
@@ -1312,7 +1312,7 @@ namespace SabreTools.Library.DatFiles
 		/// Get the keys from the file dictionary
 		/// </summary>
 		/// <returns>IEnumerable of the keys</returns>
-		public IEnumerable<string> Keys
+		public List<string> Keys
 		{
 			get
 			{
@@ -1324,7 +1324,7 @@ namespace SabreTools.Library.DatFiles
 
 				lock (_items)
 				{
-					return _items.Keys;
+					return _items.Keys.ToList();
 				}
 			}
 		}
@@ -1433,7 +1433,7 @@ namespace SabreTools.Library.DatFiles
 				_sortedBy = bucketBy;
 
 				// First do the initial sort of all of the roms inplace
-				List<string> oldkeys = Keys.ToList();
+				List<string> oldkeys = Keys;
 				Parallel.ForEach(oldkeys, Globals.ParallelOptions, key =>
 				{
 					// Get the unsorted current list
@@ -1455,7 +1455,7 @@ namespace SabreTools.Library.DatFiles
 			}
 
 			// Now go through and sort all of the individual lists
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				// Get the possibly unsorted list
@@ -1707,7 +1707,7 @@ namespace SabreTools.Library.DatFiles
 			Parallel.For(0, inputs.Count, Globals.ParallelOptions, i =>
 			{
 				// Get the list of keys from the DAT
-				List<string> keys = datHeaders[i].Keys.ToList();
+				List<string> keys = datHeaders[i].Keys;
 				foreach (string key in keys)
 				{
 					// Add everything from the key to the internal DAT
@@ -1788,20 +1788,22 @@ namespace SabreTools.Library.DatFiles
 				intDat.BucketBy(SortedBy.CRC, DedupeType.Full);
 
 				// Then we do a hashwise comparison against the base DAT
-				List<string> keys = intDat.Keys.ToList();
+				List<string> keys = intDat.Keys;
 				Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 				{
 					List<DatItem> datItems = intDat[key];
 					List<DatItem> newDatItems = new List<DatItem>();
 					foreach (DatItem datItem in datItems)
 					{
-						List<DatItem> dupes = datItem.GetDuplicates(this);
+						List<DatItem> dupes = datItem.GetDuplicates(this, sorted: true);
+						DatItem newDatItem = (DatItem)datItem.Clone();
+
 						if (dupes.Count > 0)
 						{
-							datItem.Name = dupes[0].Name;
+							newDatItem.Name = dupes[0].Name;
 						}
 
-						newDatItems.Add(datItem);
+						newDatItems.Add(newDatItem);
 					}
 
 					// Now add the new list to the key
@@ -1895,7 +1897,7 @@ namespace SabreTools.Library.DatFiles
 				intDat.BucketBy(SortedBy.CRC, DedupeType.Full);
 
 				// Then we do a hashwise comparison against the base DAT
-				List<string> keys = intDat.Keys.ToList();
+				List<string> keys = intDat.Keys;
 				Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 				{
 					List<DatItem> datItems = intDat[key];
@@ -1997,7 +1999,7 @@ namespace SabreTools.Library.DatFiles
 
 			// Now, loop through the dictionary and populate the correct DATs
 			watch.Start("Populating all output DATs");
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
@@ -2128,7 +2130,7 @@ namespace SabreTools.Library.DatFiles
 			// Now, loop through the dictionary and populate the correct DATs
 			watch.Start("Populating all output DATs");
 
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = DatItem.Merge(this[key]);
@@ -2226,7 +2228,7 @@ namespace SabreTools.Library.DatFiles
 			// If we're in SuperDAT mode, prefix all games with their respective DATs
 			if (Type == "SuperDAT")
 			{
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 				{
 					List<DatItem> items = this[key].ToList();
@@ -2352,7 +2354,7 @@ namespace SabreTools.Library.DatFiles
 			SortedDictionary<string, List<DatItem>> sorted = new SortedDictionary<string, List<DatItem>>();
 
 			// Now perform a deep clone on the entire dictionary
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			foreach (string key in keys)
 			{
 				// Clone each list of DATs in the dictionary
@@ -2414,7 +2416,7 @@ namespace SabreTools.Library.DatFiles
 			try
 			{
 				// Loop over every key in the dictionary
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				foreach (string key in keys)
 				{
 					// For every item in the current key
@@ -2471,7 +2473,7 @@ namespace SabreTools.Library.DatFiles
 			{
 				// First we want to get a mapping for all games to description
 				ConcurrentDictionary<string, string> mapping = new ConcurrentDictionary<string, string>();
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 				{
 					List<DatItem> items = this[key];
@@ -2486,7 +2488,7 @@ namespace SabreTools.Library.DatFiles
 				});
 
 				// Now we loop through every item and update accordingly
-				keys = Keys.ToList();
+				keys = Keys;
 				Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 				{
 					List<DatItem> items = this[key];
@@ -2541,7 +2543,7 @@ namespace SabreTools.Library.DatFiles
 			Globals.Logger.User("Stripping requested hashes");
 
 			// Now process all of the roms
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = this[key];
@@ -2619,7 +2621,7 @@ namespace SabreTools.Library.DatFiles
 			string pattern = @"([0-9]{2}\.[0-9]{2}\.[0-9]{2}-)(.*?-.*?)";
 
 			// Now process all of the roms
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = this[key];
@@ -2766,7 +2768,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void AddRomsFromBios()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				// If the game has no items in it, we want to continue
@@ -2814,7 +2816,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void AddRomsFromDevices()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				// If the game has no devices, we continue
@@ -2854,7 +2856,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void AddRomsFromParent()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				// If the game has no items in it, we want to continue
@@ -2910,7 +2912,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void AddRomsFromChildren()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				// Determine if the game has a parent or not
@@ -2962,7 +2964,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void RemoveBiosAndDeviceSets()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				if (this[game].Count > 0
@@ -2980,7 +2982,7 @@ namespace SabreTools.Library.DatFiles
 		private void RemoveBiosRomsFromChild()
 		{
 			// Loop through the romof tags
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				// If the game has no items in it, we want to continue
@@ -3023,7 +3025,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void RemoveRomsFromChild()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				// If the game has no items in it, we want to continue
@@ -3074,7 +3076,7 @@ namespace SabreTools.Library.DatFiles
 		/// </summary>
 		private void RemoveTagsFromChild()
 		{
-			List<string> games = Keys.ToList();
+			List<string> games = Keys;
 			foreach (string game in games)
 			{
 				List<DatItem> items = this[game];
@@ -3963,7 +3965,7 @@ namespace SabreTools.Library.DatFiles
 			BucketBy(SortedBy.SHA1, DedupeType.None);
 
 			// Then we want to loop through each of the hashes and see if we can rebuild
-			List<string> hashes = Keys.ToList();
+			List<string> hashes = Keys;
 			foreach (string hash in hashes)
 			{
 				// Pre-empt any issues that could arise from string length
@@ -4697,7 +4699,7 @@ namespace SabreTools.Library.DatFiles
 			BucketBy(SortedBy.SHA1, DedupeType.None);
 
 			// Then we want to loop through each of the hashes and see if we can rebuild
-			List<string> hashes = Keys.ToList();
+			List<string> hashes = Keys;
 			foreach (string hash in hashes)
 			{
 				// Pre-empt any issues that could arise from string length
@@ -4913,7 +4915,7 @@ namespace SabreTools.Library.DatFiles
 			}
 
 			// Now separate the roms accordingly
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = this[key];
@@ -5135,7 +5137,7 @@ namespace SabreTools.Library.DatFiles
 			};
 
 			// Now populate each of the DAT objects in turn
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = this[key];
@@ -5243,7 +5245,7 @@ namespace SabreTools.Library.DatFiles
 			};
 
 			// Sort the input keys
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			keys.Sort(SplitByLevelSort);
 
 			// Then, we loop over the games
@@ -5412,7 +5414,7 @@ namespace SabreTools.Library.DatFiles
 			};
 
 			// Now populate each of the DAT objects in turn
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = this[key];
@@ -5637,7 +5639,7 @@ namespace SabreTools.Library.DatFiles
 			}
 
 			// Loop through and add
-			List<string> keys = Keys.ToList();
+			List<string> keys = Keys;
 			Parallel.ForEach(keys, Globals.ParallelOptions, key =>
 			{
 				List<DatItem> items = this[key];
diff --git a/SabreTools.Library/DatFiles/DosCenter.cs b/SabreTools.Library/DatFiles/DosCenter.cs
index bf3cf55e..eedc50b2 100644
--- a/SabreTools.Library/DatFiles/DosCenter.cs
+++ b/SabreTools.Library/DatFiles/DosCenter.cs
@@ -90,7 +90,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/Hashfile.cs b/SabreTools.Library/DatFiles/Hashfile.cs
index 9084521e..664ef9a3 100644
--- a/SabreTools.Library/DatFiles/Hashfile.cs
+++ b/SabreTools.Library/DatFiles/Hashfile.cs
@@ -134,7 +134,7 @@ namespace SabreTools.Library.DatFiles
 				StreamWriter sw = new StreamWriter(fs, new UTF8Encoding(true));
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/Listroms.cs b/SabreTools.Library/DatFiles/Listroms.cs
index dc58fd17..5aeb18be 100644
--- a/SabreTools.Library/DatFiles/Listroms.cs
+++ b/SabreTools.Library/DatFiles/Listroms.cs
@@ -267,7 +267,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/Logiqx.cs b/SabreTools.Library/DatFiles/Logiqx.cs
index eab3d107..e594726b 100644
--- a/SabreTools.Library/DatFiles/Logiqx.cs
+++ b/SabreTools.Library/DatFiles/Logiqx.cs
@@ -1199,7 +1199,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/Missfile.cs b/SabreTools.Library/DatFiles/Missfile.cs
index 74d3d4ba..720f2413 100644
--- a/SabreTools.Library/DatFiles/Missfile.cs
+++ b/SabreTools.Library/DatFiles/Missfile.cs
@@ -88,7 +88,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/OfflineList.cs b/SabreTools.Library/DatFiles/OfflineList.cs
index a8212408..92cfdbc1 100644
--- a/SabreTools.Library/DatFiles/OfflineList.cs
+++ b/SabreTools.Library/DatFiles/OfflineList.cs
@@ -92,7 +92,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/RomCenter.cs b/SabreTools.Library/DatFiles/RomCenter.cs
index 7e99e9d5..0d150aa4 100644
--- a/SabreTools.Library/DatFiles/RomCenter.cs
+++ b/SabreTools.Library/DatFiles/RomCenter.cs
@@ -227,7 +227,7 @@ namespace SabreTools.Library.DatFiles
 				List<string> splitpath = new List<string>();
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/SabreDat.cs b/SabreTools.Library/DatFiles/SabreDat.cs
index c1dd3c58..1266b2f2 100644
--- a/SabreTools.Library/DatFiles/SabreDat.cs
+++ b/SabreTools.Library/DatFiles/SabreDat.cs
@@ -94,7 +94,7 @@ namespace SabreTools.Library.DatFiles
 				List<string> splitpath = new List<string>();
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/SeparatedValue.cs b/SabreTools.Library/DatFiles/SeparatedValue.cs
index 4d9bd367..8d1c4c8d 100644
--- a/SabreTools.Library/DatFiles/SeparatedValue.cs
+++ b/SabreTools.Library/DatFiles/SeparatedValue.cs
@@ -392,7 +392,7 @@ namespace SabreTools.Library.DatFiles
 				WriteHeader(sw, delim);
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/DatFiles/SoftwareList.cs b/SabreTools.Library/DatFiles/SoftwareList.cs
index aedc4949..b26eac74 100644
--- a/SabreTools.Library/DatFiles/SoftwareList.cs
+++ b/SabreTools.Library/DatFiles/SoftwareList.cs
@@ -94,7 +94,7 @@ namespace SabreTools.Library.DatFiles
 				string lastgame = null;
 
 				// Get a properly sorted set of keys
-				List<string> keys = Keys.ToList();
+				List<string> keys = Keys;
 				keys.Sort(new NaturalComparer());
 
 				foreach (string key in keys)
diff --git a/SabreTools.Library/Items/DatItem.cs b/SabreTools.Library/Items/DatItem.cs
index 85bfa206..1ed424ba 100644
--- a/SabreTools.Library/Items/DatItem.cs
+++ b/SabreTools.Library/Items/DatItem.cs
@@ -583,8 +583,9 @@ namespace SabreTools.Library.Items
 		/// </summary>
 		/// <param name="datdata">Dat to match against</param>
 		/// <param name="remove">True to remove matched roms from the input, false otherwise (default)</param>
+		/// <param name="sorted">True if the DAT is already sorted accordingly, false otherwise (default)</param>
 		/// <returns>List of matched DatItem objects</returns>
-		public List<DatItem> GetDuplicates(DatFile datdata, bool remove = false)
+		public List<DatItem> GetDuplicates(DatFile datdata, bool remove = false, bool sorted = false)
 		{
 			List<DatItem> output = new List<DatItem>();
 
@@ -595,7 +596,7 @@ namespace SabreTools.Library.Items
 			}
 
 			// We want to get the proper key for the DatItem
-			string key = SortAndGetKey(datdata);
+			string key = SortAndGetKey(datdata, sorted);
 
 			// If the key doesn't exist, return the empty list
 			if (!datdata.Contains(key))