diff --git a/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableSortedSet_1.cs b/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableSortedSet_1.cs
index 902e9168872cf4..2a65638c962f5c 100644
--- a/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableSortedSet_1.cs
+++ b/src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableSortedSet_1.cs
@@ -375,24 +375,71 @@ public bool SetEquals(IEnumerable<T> other)
                 return true;
             }
 
+            if (other is ICollection<T> otherAsICollectionGeneric)
+            {
+                if (otherAsICollectionGeneric.Count < this.Count)
+                {
+                    return false;
+                }
+
+                if (other is SortedSet<T> otherAsSortedSet && otherAsSortedSet.Comparer == this.KeyComparer)
+                {
+                    if (otherAsSortedSet.Count != this.Count)
+                    {
+                        return false;
+                    }
+                    var e1 = this.GetEnumerator();
+                    var e2 = otherAsSortedSet.GetEnumerator();
+                    while (e1.MoveNext() && e2.MoveNext())
+                    {
+                        if (this.KeyComparer.Compare(e1.Current, e2.Current) != 0)
+                        {
+                            return false;
+                        }
+                    }
+                    return true;
+                }
+
+                else if (other is ImmutableSortedSet<T> otherAsImmutableSortedSet && otherAsImmutableSortedSet.KeyComparer == this.KeyComparer)
+                {
+                    if (otherAsImmutableSortedSet.Count != this.Count)
+                    {
+                        return false;
+                    }
+                    var e1 = this.GetEnumerator();
+                    var e2 = otherAsImmutableSortedSet.GetEnumerator();
+                    while (e1.MoveNext() && e2.MoveNext())
+                    {
+                        if (this.KeyComparer.Compare(e1.Current, e2.Current) != 0)
+                        {
+                            return false;
+                        }
+                    }
+                    return true;
+                }
+            }
+
+            else if (other is ICollection otherAsICollection && otherAsICollection.Count < this.Count)
+            {
+                return false;
+            }
+
             var otherSet = new SortedSet<T>(other, this.KeyComparer);
             if (this.Count != otherSet.Count)
             {
                 return false;
             }
-
-            int matches = 0;
-            foreach (T item in otherSet)
+            var thisEnumerator = this.GetEnumerator();
+            var otherSetEnumerator = otherSet.GetEnumerator();
+            while (otherSetEnumerator.MoveNext() && thisEnumerator.MoveNext())
             {
-                if (!this.Contains(item))
+                if (this.KeyComparer.Compare(otherSetEnumerator.Current, thisEnumerator.Current) != 0)
                 {
                     return false;
                 }
-
-                matches++;
             }
 
-            return matches == this.Count;
+            return true;
         }
 
         /// <summary>