diff --git a/neo/Helper.cs b/neo/Helper.cs
index 4f7db112a2..6f3ae05c6d 100644
--- a/neo/Helper.cs
+++ b/neo/Helper.cs
@@ -56,7 +56,7 @@ internal static int GetLowestSetBit(this BigInteger i)
 
         internal static void Remove<T>(this HashSet<T> set, IEnumerable<T> remove)
         {
-            if (set.Count > 1000)
+            if (set.Count > 600000)
             {
                 set.ExceptWith(remove);
             }