diff --git a/src/Helpers_TEST.cc b/src/Helpers_TEST.cc
index 21bf2ac0e..36741ee25 100644
--- a/src/Helpers_TEST.cc
+++ b/src/Helpers_TEST.cc
@@ -501,9 +501,13 @@ TEST(HelpersTest, Pair)
 
 #if !defined _MSC_VER && !defined __arm__
     // Iterate over large numbers, and check for unique keys.
-    for (math::PairInput a = math::MAX_UI32-5000; a < math::MAX_UI32; a++)
+    for (math::PairInput a = math::MAX_UI32 - 10000; 
+         a < math::MAX_UI32 - 500; 
+         a += math::Rand::IntUniform(100, 500))
     {
-      for (math::PairInput b = math::MAX_UI32-5000; b < math::MAX_UI32; b++)
+      for (math::PairInput b = math::MAX_UI32 - 10000; 
+           b < math::MAX_UI32 - 500; 
+           b += math::Rand::IntUniform(100, 500))
       {
         math::PairOutput key = math::Pair(a, b);
         std::tie(c, d) = math::Unpair(key);
@@ -514,6 +518,8 @@ TEST(HelpersTest, Pair)
         set.insert(key);
       }
     }
+
+    std::cout << "Tested: " << set.size() << " keys\n.";
 #endif
   }
 }