diff --git a/tests/pathological/test.php b/tests/pathological/test.php
index 854071ca41..77664b55c2 100755
--- a/tests/pathological/test.php
+++ b/tests/pathological/test.php
@@ -300,8 +300,8 @@
             $timeout = 5; // 5 seconds
         } else {
             // Ideally, these cases should run in linear time or better,
-            // but we'll allow a 50% margin of error.
-            $timeout = \ceil($lastRunTime * $inputSize / $lastInputSize * 1.5);
+            // but we'll allow a 2x margin of error.
+            $timeout = \ceil($lastRunTime * $inputSize / $lastInputSize * 2);
             // But regardless of this, we always want to wait at least 5 seconds,
             // and at most 60 seconds.
             $timeout = \max(5, \min(60, $timeout));