diff --git a/src/DotRecast.Detour.Crowd/DtCrowd.cs b/src/DotRecast.Detour.Crowd/DtCrowd.cs
index 19b48ec..acf85e7 100644
--- a/src/DotRecast.Detour.Crowd/DtCrowd.cs
+++ b/src/DotRecast.Detour.Crowd/DtCrowd.cs
@@ -886,17 +886,19 @@ namespace DotRecast.Detour.Crowd
                 }
 
                 // Query neighbour agents
-                ag.neis = GetNeighbours(ag.npos, ag.option.height, ag.option.collisionQueryRange, ag, _grid);
+                GetNeighbours(ag.npos, ag.option.height, ag.option.collisionQueryRange, ag, ref ag.neis, _grid);
             }
 
             _telemetry.Stop("buildNeighbours");
         }
 
 
-        private List<DtCrowdNeighbour> GetNeighbours(RcVec3f pos, float height, float range, DtCrowdAgent skip, DtProximityGrid grid)
+        private int GetNeighbours(RcVec3f pos, float height, float range, DtCrowdAgent skip, ref List<DtCrowdNeighbour> result, DtProximityGrid grid)
         {
-            HashSet<DtCrowdAgent> proxAgents = grid.QueryItems(pos.x - range, pos.z - range, pos.x + range, pos.z + range);
-            List<DtCrowdNeighbour> result = new List<DtCrowdNeighbour>(proxAgents.Count);
+            result.Clear();
+
+            var proxAgents = new HashSet<DtCrowdAgent>();
+            int nids = grid.QueryItems(pos.x - range, pos.z - range, pos.x + range, pos.z + range, ref proxAgents);
             foreach (DtCrowdAgent ag in proxAgents)
             {
                 if (ag == skip)
@@ -922,7 +924,7 @@ namespace DotRecast.Detour.Crowd
             }
 
             result.Sort((o1, o2) => o1.dist.CompareTo(o2.dist));
-            return result;
+            return result.Count;
         }
 
         private void FindCorners(IList<DtCrowdAgent> agents, DtCrowdAgentDebugInfo debug)
diff --git a/src/DotRecast.Detour.Crowd/DtCrowdNeighbour.cs b/src/DotRecast.Detour.Crowd/DtCrowdNeighbour.cs
index 79b0c64..5f19093 100644
--- a/src/DotRecast.Detour.Crowd/DtCrowdNeighbour.cs
+++ b/src/DotRecast.Detour.Crowd/DtCrowdNeighbour.cs
@@ -3,7 +3,7 @@
     /// Provides neighbor data for agents managed by the crowd.
     /// @ingroup crowd
     /// @see dtCrowdAgent::neis, dtCrowd
-    public class DtCrowdNeighbour
+    public readonly struct DtCrowdNeighbour
     {
         public readonly DtCrowdAgent agent;
 
diff --git a/src/DotRecast.Detour.Crowd/DtProximityGrid.cs b/src/DotRecast.Detour.Crowd/DtProximityGrid.cs
index 92b5ea4..d69ca8d 100644
--- a/src/DotRecast.Detour.Crowd/DtProximityGrid.cs
+++ b/src/DotRecast.Detour.Crowd/DtProximityGrid.cs
@@ -81,14 +81,13 @@ namespace DotRecast.Detour.Crowd
         }
 
         // 해당 셀 사이즈의 크기로 x ~ y 영역을 찾아, 군집 에이전트를 가져오는 코드
-        public HashSet<DtCrowdAgent> QueryItems(float minx, float miny, float maxx, float maxy)
+        public int QueryItems(float minx, float miny, float maxx, float maxy, ref HashSet<DtCrowdAgent> result)
         {
             int iminx = (int)Math.Floor(minx * _invCellSize);
             int iminy = (int)Math.Floor(miny * _invCellSize);
             int imaxx = (int)Math.Floor(maxx * _invCellSize);
             int imaxy = (int)Math.Floor(maxy * _invCellSize);
 
-            HashSet<DtCrowdAgent> result = new HashSet<DtCrowdAgent>();
             for (int y = iminy; y <= imaxy; ++y)
             {
                 for (int x = iminx; x <= imaxx; ++x)
@@ -104,7 +103,7 @@ namespace DotRecast.Detour.Crowd
                 }
             }
 
-            return result;
+            return result.Count;
         }
 
         public IEnumerable<(long, int)> GetItemCounts()