diff --git a/AetherBags/Helpers/RegexCache.cs b/AetherBags/Helpers/RegexCache.cs
new file mode 100644
index 0000000..b6ee376
--- /dev/null
+++ b/AetherBags/Helpers/RegexCache.cs
@@ -0,0 +1,47 @@
+using System.Collections.Concurrent;
+using System.Text.RegularExpressions;
+
+namespace AetherBags.Helpers;
+
+/// <summary>
+/// Thread-safe cache for compiled Regex objects to avoid repeated compilation overhead.
+/// </summary>
+internal static class RegexCache
+{
+    private const int MaxCacheSize = 128;
+    private static readonly ConcurrentDictionary<string, Regex> Cache = new();
+
+    /// <summary>
+    /// Gets or creates a compiled Regex for the given pattern with case-insensitive matching.
+    /// Returns null if the pattern is invalid.
+    /// </summary>
+    public static Regex? GetOrCreate(string pattern)
+    {
+        if (string.IsNullOrEmpty(pattern))
+            return null;
+
+        if (Cache.TryGetValue(pattern, out var cached))
+            return cached;
+
+        try
+        {
+            var regex = new Regex(pattern, RegexOptions.CultureInvariant | RegexOptions.IgnoreCase | RegexOptions.Compiled);
+
+            if (Cache.Count < MaxCacheSize)
+            {
+                Cache.TryAdd(pattern, regex);
+            }
+
+            return regex;
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    /// <summary>
+    /// Clears the regex cache. Call when configuration changes significantly.
+    /// </summary>
+    public static void Clear() => Cache.Clear();
+}
diff --git a/AetherBags/Inventory/Categories/CategoryBucket.cs b/AetherBags/Inventory/Categories/CategoryBucket.cs
index 3dda341..b1b9695 100644
--- a/AetherBags/Inventory/Categories/CategoryBucket.cs
+++ b/AetherBags/Inventory/Categories/CategoryBucket.cs
@@ -10,6 +10,7 @@ public sealed class CategoryBucket
     public List<ItemInfo> Items = null!;
     public List<ItemInfo> FilteredItems = null!;
     public bool Used;
+    public bool NeedsSorting = true;
 }
 
 public sealed class ItemCountDescComparer : IComparer<ItemInfo>
diff --git a/AetherBags/Inventory/Categories/CategoryBucketManager.cs b/AetherBags/Inventory/Categories/CategoryBucketManager.cs
index b24db77..227593b 100644
--- a/AetherBags/Inventory/Categories/CategoryBucketManager.cs
+++ b/AetherBags/Inventory/Categories/CategoryBucketManager.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using AetherBags.Configuration;
 using AetherBags.Inventory.Items;
 using KamiToolKit.Classes;
@@ -49,6 +48,7 @@ public static class CategoryBucketManager
             bucket.Used = false;
             bucket.Items.Clear();
             bucket.FilteredItems.Clear();
+            bucket.NeedsSorting = true;
         }
     }
 
@@ -302,8 +302,9 @@ public static class CategoryBucketManager
             CategoryInfo miscInfo;
             if (itemInfoByKey.Count > 0)
             {
-                var sample = itemInfoByKey.Values.First();
-                miscInfo = GetCategoryInfoCached(0u, sample);
+                using var enumerator = itemInfoByKey.Values.GetEnumerator();
+                enumerator.MoveNext();
+                miscInfo = GetCategoryInfoCached(0u, enumerator.Current);
             }
             else
             {
@@ -353,7 +354,12 @@ public static class CategoryBucketManager
                 continue;
 
             // TODO: Make configurable
-            bucket.Items.Sort(ItemCountDescComparer.Instance);
+            // Only sort if items changed
+            if (bucket.NeedsSorting)
+            {
+                bucket.Items.Sort(ItemCountDescComparer.Instance);
+                bucket.NeedsSorting = false;
+            }
             sortedCategoryKeys.Add(bucket.Key);
         }
 
diff --git a/AetherBags/Inventory/Categories/InventoryFilter.cs b/AetherBags/Inventory/Categories/InventoryFilter.cs
index 42d91ca..a35f7f6 100644
--- a/AetherBags/Inventory/Categories/InventoryFilter.cs
+++ b/AetherBags/Inventory/Categories/InventoryFilter.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
+using AetherBags.Helpers;
 using AetherBags.Inventory.Items;
 
 namespace AetherBags.Inventory.Categories;
@@ -17,17 +18,8 @@ public static class InventoryFilter
         if (string.IsNullOrEmpty(filterString))
             return allCategories;
 
-        Regex? re = null;
-        bool regexValid = true;
-
-        try
-        {
-            re = new Regex(filterString, RegexOptions.CultureInvariant | RegexOptions.IgnoreCase);
-        }
-        catch
-        {
-            regexValid = false;
-        }
+        Regex? re = RegexCache.GetOrCreate(filterString);
+        bool regexValid = re != null;
 
         filteredCategories.Clear();
 
diff --git a/AetherBags/Inventory/Categories/UserCategoryMatcher.cs b/AetherBags/Inventory/Categories/UserCategoryMatcher.cs
index 32edcdb..ea33e63 100644
--- a/AetherBags/Inventory/Categories/UserCategoryMatcher.cs
+++ b/AetherBags/Inventory/Categories/UserCategoryMatcher.cs
@@ -1,6 +1,6 @@
 using System;
-using System.Text.RegularExpressions;
 using AetherBags.Configuration;
+using AetherBags.Helpers;
 using AetherBags.Inventory.Items;
 
 namespace AetherBags.Inventory.Categories;
@@ -30,17 +30,11 @@ internal static class UserCategoryMatcher
                     if (string.IsNullOrWhiteSpace(pattern))
                         continue;
 
-                    try
+                    var regex = RegexCache.GetOrCreate(pattern);
+                    if (regex != null && regex.IsMatch(item.Name))
                     {
-                        if (Regex.IsMatch(item.Name, pattern, RegexOptions.CultureInvariant | RegexOptions.IgnoreCase))
-                        {
-                            matchesAnyIdentification = true;
-                            break;
-                        }
-                    }
-                    catch
-                    {
-                        // Invalid regex:  ignore it.
+                        matchesAnyIdentification = true;
+                        break;
                     }
                 }
             }
diff --git a/AetherBags/Inventory/Context/HighlightState.cs b/AetherBags/Inventory/Context/HighlightState.cs
index a763d49..00dd134 100644
--- a/AetherBags/Inventory/Context/HighlightState.cs
+++ b/AetherBags/Inventory/Context/HighlightState.cs
@@ -18,13 +18,27 @@ public static class HighlightState
     private static readonly Dictionary<HighlightSource, (HashSet<uint> ids, Vector3 color)> Labels = new();
     private static readonly Dictionary<HighlightSource, Dictionary<uint, HighlightEntry>> PerItemLabels = new();
 
+    // Flat cache for O(1) lookups
+    private static readonly Dictionary<uint, HighlightEntry> CachedEntries = new(capacity: 512);
+    private static bool _cacheValid;
+    private static int _version;
+
+    /// <summary>
+    /// Version counter that increments when highlight state changes.
+    /// Used by ItemInfo to detect when cached visual state is stale.
+    /// </summary>
+    public static int Version => _version;
+
     public static string? SelectedAllaganToolsFilterKey { get; set; } = string.Empty;
     public static string? SelectedBisBuddyFilterKey { get; set; } = string.Empty;
 
     public static bool IsFilterActive => Filters.Count > 0;
 
     public static void SetFilter(HighlightSource source, IEnumerable<uint> ids)
-        => Filters[source] = new HashSet<uint>(ids);
+    {
+        Filters[source] = new HashSet<uint>(ids);
+        _version++;
+    }
 
     public static bool IsInActiveFilters(uint itemId)
     {
@@ -36,19 +50,42 @@ public static class HighlightState
 
     public static HighlightEntry? GetHighlightEntry(uint itemId)
     {
+        EnsureCacheValid();
+        return CachedEntries.TryGetValue(itemId, out var entry) ? entry : null;
+    }
+
+    private static void EnsureCacheValid()
+    {
+        if (_cacheValid) return;
+
+        CachedEntries.Clear();
+
+        // PerItemLabels have priority - add them first
         foreach (var perItemLabel in PerItemLabels.Values)
         {
-            if (perItemLabel.TryGetValue(itemId, out var entry))
-                return entry;
+            foreach (var (id, entry) in perItemLabel)
+            {
+                CachedEntries.TryAdd(id, entry);
+            }
         }
 
+        // Labels are fallback - only add if not already present
         foreach (var label in Labels.Values)
         {
-            if (label.ids.Contains(itemId))
-                return new HighlightEntry(itemId, label.color);
+            var color = label.color;
+            foreach (var id in label.ids)
+            {
+                CachedEntries.TryAdd(id, new HighlightEntry(id, color));
+            }
         }
 
-        return null;
+        _cacheValid = true;
+    }
+
+    private static void InvalidateCache()
+    {
+        _cacheValid = false;
+        _version++;
     }
 
     public static Vector3? GetLabelColor(uint itemId)
@@ -58,6 +95,7 @@ public static class HighlightState
     {
         PerItemLabels.Remove(source);
         Labels[source] = (new HashSet<uint>(ids), color);
+        InvalidateCache();
     }
 
     public static void SetLabelWithColors(HighlightSource source, Dictionary<uint, Vector4> itemColors)
@@ -76,6 +114,7 @@ public static class HighlightState
         }
 
         PerItemLabels[source] = entries;
+        InvalidateCache();
     }
 
     public static void SetLabelWithColors(HighlightSource source, IEnumerable<HighlightEntry> entries)
@@ -89,6 +128,7 @@ public static class HighlightState
         }
 
         PerItemLabels[source] = dict;
+        InvalidateCache();
     }
 
     public static void SetLabelWithColors(HighlightSource source, Dictionary<uint, Vector3> itemColors)
@@ -102,6 +142,7 @@ public static class HighlightState
         }
 
         PerItemLabels[source] = entries;
+        InvalidateCache();
     }
 
     public static void ClearAll()
@@ -109,14 +150,22 @@ public static class HighlightState
         Filters.Clear();
         Labels.Clear();
         PerItemLabels.Clear();
+        CachedEntries.Clear();
+        _cacheValid = true; // Empty cache is valid
+        _version++;
         SelectedAllaganToolsFilterKey = string.Empty;
     }
 
-    public static void ClearFilter(HighlightSource source) => Filters.Remove(source);
+    public static void ClearFilter(HighlightSource source)
+    {
+        Filters.Remove(source);
+        _version++;
+    }
 
     public static void ClearLabel(HighlightSource source)
     {
         Labels.Remove(source);
         PerItemLabels.Remove(source);
+        InvalidateCache();
     }
 }
\ No newline at end of file
diff --git a/AetherBags/Inventory/Items/ItemInfo.cs b/AetherBags/Inventory/Items/ItemInfo.cs
index b4a59fd..1a7d822 100644
--- a/AetherBags/Inventory/Items/ItemInfo.cs
+++ b/AetherBags/Inventory/Items/ItemInfo.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Numerics;
 using System.Text.RegularExpressions;
+using AetherBags.Helpers;
 using AetherBags.Inventory.Context;
 using FFXIVClientStructs.FFXIV.Client.Game;
 using Lumina.Excel;
@@ -23,6 +24,12 @@ public sealed class ItemInfo : IEquatable<ItemInfo>
 
     private string? _name;
     private string? _description;
+    private string? _levelString;
+    private string? _itemLevelString;
+
+    private int _cachedHighlightVersion = -1;
+    private float _cachedVisualAlpha;
+    private Vector3 _cachedHighlightColor;
 
     private ref readonly Item Row
     {
@@ -44,6 +51,8 @@ public sealed class ItemInfo : IEquatable<ItemInfo>
 
     public int Level => Row.LevelEquip;
     public int ItemLevel => (int)Row.LevelItem.RowId;
+    private string LevelString => _levelString ??= Level.ToString();
+    private string ItemLevelString => _itemLevelString ??= ItemLevel.ToString();
     public int Rarity => Row.Rarity;
     public uint VendorPrice => Row.PriceLow;
     public uint StackSize => Row.StackSize;
@@ -90,19 +99,37 @@ public sealed class ItemInfo : IEquatable<ItemInfo>
         }
     }
 
-    public float VisualAlpha => IsEligibleForContext ? 1.0f : 0.4f;
+    public float VisualAlpha
+    {
+        get
+        {
+            EnsureVisualStateCached();
+            return _cachedVisualAlpha;
+        }
+    }
 
     public Vector3 HighlightOverlayColor
     {
         get
         {
-            if (!System.Config.Categories.BisBuddyEnabled)
-                return Vector3.Zero;
-
-            return HighlightState.GetLabelColor(Item.ItemId) ?? Vector3.Zero;
+            EnsureVisualStateCached();
+            return _cachedHighlightColor;
         }
     }
 
+    private void EnsureVisualStateCached()
+    {
+        int currentVersion = HighlightState.Version;
+        if (_cachedHighlightVersion == currentVersion)
+            return;
+
+        _cachedVisualAlpha = IsEligibleForContext ? 1.0f : 0.4f;
+        _cachedHighlightColor = System.Config.Categories.BisBuddyEnabled
+            ? HighlightState.GetLabelColor(Item.ItemId) ?? Vector3.Zero
+            : Vector3.Zero;
+        _cachedHighlightVersion = currentVersion;
+    }
+
     private bool CheckNativeContextEligibility()
     {
         uint contextId = InventoryContextState.ActiveContextId;
@@ -138,14 +165,16 @@ public sealed class ItemInfo : IEquatable<ItemInfo>
         if (string.IsNullOrEmpty(searchTerms))
             return true;
 
-        var re = new Regex(searchTerms, RegexOptions.CultureInvariant | RegexOptions.IgnoreCase);
+        var re = RegexCache.GetOrCreate(searchTerms);
+        if (re == null)
+            return false;
 
         if (re.IsMatch(Name)) return true;
 
         if (re.IsMatch(Description)) return true;
 
-        if (re.IsMatch(Level.ToString())) return true;
-        if (re.IsMatch(ItemLevel.ToString())) return true;
+        if (re.IsMatch(LevelString)) return true;
+        if (re.IsMatch(ItemLevelString)) return true;
 
         return false;
     }
@@ -155,8 +184,8 @@ public sealed class ItemInfo : IEquatable<ItemInfo>
         if (re.IsMatch(Name)) return true;
         if (re.IsMatch(Description)) return true;
 
-        if (re.IsMatch(Level.ToString())) return true;
-        if (re.IsMatch(ItemLevel.ToString())) return true;
+        if (re.IsMatch(LevelString)) return true;
+        if (re.IsMatch(ItemLevelString)) return true;
 
         return false;
     }
diff --git a/AetherBags/Inventory/State/InventoryStateBase.cs b/AetherBags/Inventory/State/InventoryStateBase.cs
index c4d9cc1..9f0ed23 100644
--- a/AetherBags/Inventory/State/InventoryStateBase.cs
+++ b/AetherBags/Inventory/State/InventoryStateBase.cs
@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using System.Linq;
 using AetherBags.Configuration;
 using AetherBags.Currency;
 using AetherBags.Inventory.Categories;
@@ -109,7 +108,7 @@ public abstract class InventoryStateBase
             }
             else
             {
-                UpdateAllaganHighlight(HighlightState.SelectedBisBuddyFilterKey);
+                UpdateBisBuddyHighlight(HighlightState.SelectedBisBuddyFilterKey);
             }
         }
         else
@@ -156,10 +155,10 @@ public abstract class InventoryStateBase
             return;
         }
 
-        var filterItems = System.IPC.AllaganTools.GetFilterItems(filterKey);
-        if (filterItems != null)
+        var bisItems = System.IPC.BisBuddy.ItemLookup;
+        if (bisItems.Count > 0)
         {
-            HighlightState.SetFilter(HighlightSource.BiSBuddy, filterItems.Keys);
+            HighlightState.SetFilter(HighlightSource.BiSBuddy, bisItems.Keys);
         }
         else
         {