diff --git a/PerfectNumbers.Core/PrimeOrderCalculator.cs b/PerfectNumbers.Core/PrimeOrderCalculator.cs
index fd2da4b..75c9cd3 100644
--- a/PerfectNumbers.Core/PrimeOrderCalculator.cs
+++ b/PerfectNumbers.Core/PrimeOrderCalculator.cs
@@ -10,15 +10,23 @@ internal static partial class PrimeOrderCalculator
 
 	internal readonly struct PrimeOrderSearchConfig(uint smallFactorLimit, int pollardRhoMilliseconds, int maxPowChecks, PrimeOrderMode mode)
 	{
+		private static PrimeOrderSearchConfig _heuristicDefault = CreateHeuristicDefault(UnboundedTaskScheduler.ConfiguredThreadCount);
+
 		public static PrimeOrderSearchConfig HeuristicDefault
 		{
 				get
 				{
-					return CreateHeuristicDefault(UnboundedTaskScheduler.ConfiguredThreadCount);
+					return _heuristicDefault;
 				}
 		}
+
 		public static readonly PrimeOrderSearchConfig StrictDefault = new(smallFactorLimit: 1_000_000, pollardRhoMilliseconds: 0, maxPowChecks: 0, PrimeOrderMode.Strict);
 
+		public static void ConfigureHeuristicDefault(int threadCount)
+		{
+				_heuristicDefault = CreateHeuristicDefault(threadCount);
+		}
+
 		public static PrimeOrderSearchConfig CreateHeuristicDefault(int threadCount)
 		{
 				int normalizedThreadCount = threadCount < 1 ? 1 : threadCount;
diff --git a/PerfectNumbers.Core/UnboundedTaskScheduler.cs b/PerfectNumbers.Core/UnboundedTaskScheduler.cs
index 66912e9..cbfe5fd 100644
--- a/PerfectNumbers.Core/UnboundedTaskScheduler.cs
+++ b/PerfectNumbers.Core/UnboundedTaskScheduler.cs
@@ -40,6 +40,7 @@ public sealed class UnboundedTaskScheduler : TaskScheduler
         lock (InstanceLock)
         {
             Volatile.Write(ref _configuredThreadCount, normalizedThreadCount);
+            PrimeOrderCalculator.PrimeOrderSearchConfig.ConfigureHeuristicDefault(normalizedThreadCount);
 
             if (_instance is null)
             {