diff --git a/tests/ImageSharp.Tests/Helpers/ParallelHelperTests.cs b/tests/ImageSharp.Tests/Helpers/ParallelHelperTests.cs
index 69942eef9..f9db1a429 100644
--- a/tests/ImageSharp.Tests/Helpers/ParallelHelperTests.cs
+++ b/tests/ImageSharp.Tests/Helpers/ParallelHelperTests.cs
@@ -39,7 +39,10 @@ namespace SixLabors.ImageSharp.Tests.Helpers
                     { 4, 123, 323, 50, 50, 4 },
                     { 4, 0, 1201, 301, 298, 4 },
                     { 8, 10, 236, 29, 23, 8 },
-                    { 16, 0, 209, 14, 13, 15 }
+                    { 16, 0, 209, 14, 13, 15 },
+                    { 24, 0, 209, 9, 2, 24 },
+                    { 32, 0, 209, 7, 6, 30 },
+                    { 64, 0, 209, 4, 1, 53 },
                 };
 
         [Theory]